Systems and methods for positioning reference signal staggering configuration

ABSTRACT

Disclosed are methods and apparatuses for resolving aliasing ambiguities produced when using channel state information reference signal, a sounding reference signal (SRS) or other transmission as a positioning reference signal (PRS) occupying a subset of tones of a PRS bandwidth. The aliasing ambiguity results in a plurality of different possible positioning measurements, such as time of arrival (TOA), reference signal timing difference (RSTD), or reception to transmission difference (Rx−Tx). The aliasing ambiguity may be resolved using a previous position estimate that may be used to produce an approximation of the expected positioning measurement. A position estimate may be generated using a multiple stage PRS configuration, in which one or more stages provide a coarse position estimate that has no ambiguity, which can be used to resolve the ambiguity of a more accurate position estimate resulting from the PRS signal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Greek Patent Application No.20190100184, entitled “SYSTEMS AND METHODS FOR POSITIONING REFERENCESIGNAL STAGGERING CONFIGURATION,” filed Apr. 25, 2019, which is assignedto the assignee hereof and which is expressly incorporated herein byreference in its entirety.

TECHNICAL FIELD

The following relates generally to wireless communications, and morespecifically to techniques for supporting location services for userequipments (UEs) in a wireless network.

DESCRIPTION OF THE RELATED TECHNOLOGY

Wireless communications systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be capable ofsupporting communication with multiple users by sharing the availablesystem resources (for example, time, frequency, and power). Examples ofsuch multiple-access systems include fourth generation (4G) systems suchas Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, orLTE-A Pro systems, and fifth generation (5G) systems which may bereferred to as New Radio (NR) systems. These systems may employtechnologies such as code division multiple access (CDMA), time divisionmultiple access (TDMA), frequency division multiple access (FDMA),orthogonal frequency division multiple access (OFDMA), or discreteFourier transform spread orthogonal frequency division multiplexing(DFT-S-OFDM). A wireless multiple-access communications system mayinclude a number of base stations or network access nodes, eachsimultaneously supporting communication for multiple communicationdevices, which may be otherwise known as user equipment (UE).

In some wireless communications systems, a positioning engine (such as aposition measurement function (PMF), LMF, eSMLC) may determine aposition or location of a supported UE using radio access networkinformation. The information may be associated with UE-assistedpositioning techniques, such as a reference signal transmission, by thebase station and reporting of radio signaling measurements by the UE.These methods may support various location services (for example,navigation systems, emergency communications), and supplement one ormore additional location systems supported by wireless communicationsdevices (such as global positioning system (GPS) technology). As datatraffic increases, however, other reporting of radio signalingmeasurements fail to provide robust signaling and communication withinsome environments, including in new radio (NR) systems. Improvedtechniques and systems are desired.

SUMMARY

Disclosed are methods and apparatuses for resolving aliasing ambiguitiesproduced when using channel state information reference signal, asounding reference signal (SRS) or other transmission as a positioningreference signal (PRS) occupying a subset of tones of a PRS bandwidth.The aliasing ambiguity results in a plurality of different possiblepositioning measurements, such as time of arrival (TOA), referencesignal timing difference (RSTD), or reception to transmission difference(Rx−Tx). The aliasing ambiguity may be resolved using a previousposition estimate that may be used to produce an approximation of theexpected positioning measurement. A position estimate may be generatedusing a multiple stage PRS configuration, in which one or more stagesprovide a coarse position estimate that has no ambiguity, which can beused to resolve the ambiguity of a more accurate position estimateresulting from the PRS signal.

In one implementation, a method for position location performed by auser equipment (UE), includes receiving from a base station apositioning reference signal (PRS) signal occupying a subset of tones ofa PRS bandwidth, wherein the subset of tones of the PRS bandwidthproduces a plurality of possible positioning results; and determining atrue positioning measurement result based on the plurality of possiblepositioning measurement results from the received PRS signal.

In one implementation, a user equipment (UE) configured for performingposition location, includes a wireless transceiver configured tocommunicate with base stations in a wireless network; at least onememory; and at least one processor coupled to the wireless transceiverand the at least one memory, the at least one processor configured to:receive from a base station, via the wireless transceiver, a positioningreference signal (PRS) signal occupying a subset of tones of a PRSbandwidth, wherein the subset of tones of the PRS bandwidth produces aplurality of possible positioning results; and determine a truepositioning measurement result based on the plurality of possiblepositioning measurement results from the received PRS signal.

In one implementation, a user equipment (UE) configured for performingposition location, includes means for receiving from a base station apositioning reference signal (PRS) signal occupying a subset of tones ofa PRS bandwidth, wherein the subset of tones of the PRS bandwidthproduces a plurality of possible positioning results; and means fordetermining a true positioning measurement result based on the pluralityof possible positioning measurement results from the received PRSsignal.

In one implementation, a non-transitory computer readable storage mediumincluding program code stored thereon, the program code is operable toconfigure at least one processor in a user equipment (UE) capable ofsupporting position location, includes program code to receive from abase station a positioning reference signal (PRS) signal occupying asubset of tones of a PRS bandwidth, wherein the subset of tones of thePRS bandwidth produces a plurality of possible positioning results; andprogram code to determine a true positioning measurement result based onthe plurality of possible positioning measurement results from thereceived PRS signal.

In one implementation, a method for position location for a userequipment (UE) performed by a base station in a wireless network,includes receiving from the UE a positioning reference signal (PRS)signal occupying a subset of tones of a PRS bandwidth, wherein thesubset of tones of the PRS bandwidth produces a plurality of possiblepositioning results; and sending a location information to a positioningengine in the wireless network based on the PRS signal for thepositioning engine to determine a true positioning measurement resultbased on the plurality of possible positioning measurement results fromthe received PRS signal.

In one implementation, a base station in a wireless network configuredfor position location for a user equipment (UE), includes a wirelesstransceiver configured to communicate with UEs in the wireless network;at least one memory; and at least one processor coupled to the wirelesstransceiver and the at least one memory, the at least one processorconfigured to: receive from the UE, via the wireless transceiver, apositioning reference signal (PRS) signal occupying a subset of tones ofa PRS bandwidth, wherein the subset of tones of the PRS bandwidthproduces a plurality of possible positioning results; and send, via thewireless transceiver, a location information to a positioning engine inthe wireless network based on the PRS signal for the positioning engineto determine a true positioning measurement result based on theplurality of possible positioning measurement results from the receivedPRS signal.

In one implementation, a base station in a wireless network configuredfor position location for a user equipment (UE), includes means forreceiving from the UE a positioning reference signal (PRS) signaloccupying a subset of tones of a PRS bandwidth, wherein the subset oftones of the PRS bandwidth produces a plurality of possible positioningresults; and means for sending a location information to a positioningengine in the wireless network based on the PRS signal for thepositioning engine to determine a true positioning measurement resultbased on the plurality of possible positioning measurement results fromthe received PRS signal.

In one implementation, a non-transitory computer readable storage mediumincluding program code stored thereon, the program code is operable toconfigure at least one processor in a base station in a wireless networkcapable of supporting position location for a user equipment (UE),includes program code to receive from the UE a positioning referencesignal (PRS) signal occupying a subset of tones of a PRS bandwidth,wherein the subset of tones of the PRS bandwidth produces a plurality ofpossible positioning results; and program code to send a locationinformation to a positioning engine in the wireless network based on thePRS signal for the positioning engine to determine a true positioningmeasurement result based on the plurality of possible positioningmeasurement results from the received PRS signal.

In one implementation, a method for position location for a userequipment (UE) performed by a positioning engine in a wireless network,includes receiving location information from a first entity in thewireless network determined from a positioning reference signal (PRS)signal occupying a subset of tones of a PRS bandwidth, received by thefirst entity from a second entity in the wireless network, wherein thefirst entity is one of the UE and a base station and the second entityis the other of the UE and the base station, wherein the subset of tonesof the PRS bandwidth produces a plurality of possible positioningresults; and determining a true positioning measurement result based onthe plurality of possible positioning measurement results from thereceived location information.

In one implementation, a positioning engine in a wireless networkconfigured for position location for a user equipment (UE), includes awireless transceiver configured to communicate with entities in thewireless network; at least one memory; and at least one processorcoupled to the wireless transceiver and the at least one memory, the atleast one processor configured to: receive, via the wirelesstransceiver, location information from a first entity in the wirelessnetwork determined from a positioning reference signal (PRS) signaloccupying a subset of tones of a PRS bandwidth, received by the firstentity from a second entity in the wireless network, wherein the firstentity is one of the UE and a base station and the second entity is theother of the UE and the base station, wherein the subset of tones of thePRS bandwidth produces a plurality of possible positioning results; anddetermine a true positioning measurement result based on the pluralityof possible positioning measurement results from the received locationinformation.

In one implementation, a positioning engine in a wireless networkconfigured for position location for a user equipment (UE), includesmeans for receiving location information from a first entity in thewireless network determined from a positioning reference signal (PRS)signal occupying a subset of tones of a PRS bandwidth, received by thefirst entity from a second entity in the wireless network, wherein thefirst entity is one of the UE and a base station and the second entityis the other of the UE and the base station, wherein the subset of tonesof the PRS bandwidth produces a plurality of possible positioningresults; and means for determining a true positioning measurement resultbased on the plurality of possible positioning measurement results fromthe received location information.

In one implementation, a non-transitory computer readable storage mediumincluding program code stored thereon, the program code is operable toconfigure at least one processor in a positioning engine in a wirelessnetwork capable of supporting position location for a user equipment(UE), includes program code to receive location information from a firstentity in the wireless network determined from a positioning referencesignal (PRS) signal occupying a subset of tones of a PRS bandwidth,received by the first entity from a second entity in the wirelessnetwork, wherein the first entity is one of the UE and a base stationand the second entity is the other of the UE and the base station,wherein the subset of tones of the PRS bandwidth produces a plurality ofpossible positioning results; and program code to determine a truepositioning measurement result based on the plurality of possiblepositioning measurement results from the received location information.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a wireless communications system thatsupports eliminating aliasing ambiguities produced in a comb-N PRSsignal for positioning in accordance with aspects of the presentdisclosure.

FIG. 2 is a diagram of a structure of an example LTE subframe sequencewith Positioning Reference Signaling (PRS) positioning occasions.

FIGS. 3 and 4 are diagrams illustrating further aspects of PRStransmission for a cell supported by a wireless node.

FIG. 5 is a diagram illustrating an exemplary technique for determininga position of a mobile device using information obtained from aplurality of base stations.

FIG. 6 is a diagram illustrating another exemplary technique fordetermining a position of a mobile device using information obtainedfrom a plurality of base stations.

FIGS. 7A and 7B illustrate a performance comparison between comb-1 vs.comb-4.

FIG. 8 is a graph illustrating a comb-4 channel energy response (CER)and potential alias issue according to at least one aspect of thedisclosure.

FIG. 9 illustrates an ambiguity in distances between a base station anda UE resulting from the use of a comb-4 PRS signal.

FIG. 10 illustrates a procedure which may be used to support positionmethods using downlink comb-N, N≥2, PRS signals.

FIG. 11 shows a process flow illustrating a method for position locationperformed by a user equipment in which downlink comb-N, N≥2, PRS signalsare used.

FIG. 12 shows a process flow illustrating a method for position locationperformed by a base station in which uplink comb-N, N≥2. PRS signals areused.

FIG. 13 shows a process flow illustrating a method for position locationperformed by a positioning engine in which downlink or uplink comb-N,N≥2, PRS signals are used.

FIG. 14 is a block diagram of an embodiment of a user equipment capableof supporting use of comb-N, N≥2, PRS signals.

FIG. 15 is a block diagram of an embodiment of a base station capable ofsupporting use of comb-N, N≥2, PRS signals.

FIG. 16 is a block diagram of an embodiment of a positioning enginecapable of supporting use of comb-N, N≥2, PRS signals.

DETAILED DESCRIPTION

In location determination, such as Observed Time Difference of Arrival(OTDOA) based positioning, the UE may measure time differences inreceived signals from a plurality of base stations. Because positions ofthe base stations are known, the observed time differences may be usedto calculate the location of the terminal. In OTDOA, the mobile stationmeasures the time of arrival (TOA) of signals from a reference cell(e.g., the serving cell) and one or more neighboring cells. The TOA fromthe reference cell may be subtracted from the TOA from the one or morereference cells to determine the Reference Signal Time Difference(RSTD). Using the RSTD measurements, the absolute or relativetransmission timing of each cell, and the known position(s) of thephysical transmitting antennas for the reference and neighboring cells,the UE's position may be calculated.

Positioning Reference Signals (PRS) are broadcast by base stations andare used by UEs for positioning in wireless networks, such as a LongTerm Evolution (LTE) network, and 5G NR networks, where the UE measuresthe TOA (Time of Arrival) metric of different cells and reports to thenetwork/server. Channel state information reference signal (CSI-RS)transmissions may be used as PRS signals, but they suffer from aliasingambiguities, resulting in a plurality of different possible positioningmeasurements, such as TOA, RSTD, and reception to transmissiondifference (Rx−Tx), which individually and collectively may be referredto herein as positioning measurements. For clarity, the positioningmeasurements addressed herein are timing measurements that generate theN-fold timing ambiguity when a comb-N signal is used to determine thetiming, as opposed to other non-timing related positioning measurements,such as Reference Signal Received Power (RSRP) or Angle of Arrival(AOA). Accordingly, it should be understood that positioningmeasurements as used herein are positioning-related timing measurements.

As described herein, the aliasing ambiguity may be resolved using apreviously obtained position estimate. The previously obtained positionestimate may be approximate, but sufficient to resolve the aliasingambiguity. The known position of the base station may be used with theprevious position estimate to estimate an approximate expectedpositioning measurement, e.g., TOA, RSTD, Rx−Tx, etc., which can be usedto resolve the aliasing ambiguity. For example, out of the plurality ofdifferent possible positioning measurements, the true value of thepositioning measurement may be the closest match to the expectedpositioning measurement determined from the previous position estimate.Once the expected positioning measurement is determined, e.g., by apositioning engine, a narrow search window may be configured so that outof the plurality of different possible positioning measurements only thetrue value of the positioning measurement is found within the searchwindow. The previous position estimate may be obtained, e.g., from aRadio Access Technology (RAT)-dependent, e.g., OTDOA, orRAT-independent, e.g., a Global Navigation Satellite System (GNSS)method, or a combination thereof. In one example, the previous positionestimate may be obtained using multiple stages of PRS configurations.For example, a first PRS configuration may produce an approximateposition estimate that does not suffer from aliasing ambiguities. Thecoarse position estimate from the first PRS configuration may be used toresolve the aliasing ambiguity from the second PRS configuration, whichprovides a more accurate position determination but suffers fromaliasing ambiguities. If desired, multiple PRS configurations may beused together to resolve the aliasing ambiguity.

FIG. 1 illustrates an example of a wireless communications system 100 inaccordance with one or more aspects of the present disclosure. Thewireless communications system 100 includes base stations 105, UEs 115,and a core network 130. In some examples, the wireless communicationssystem 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced(LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. Insome examples, wireless communications system 100 may support enhancedbroadband communications, ultra-reliable (for example, mission critical)communications, low latency communications, or communications withlow-cost and low-complexity devices.

Base stations 105 may wirelessly communicate with UEs 115 via one ormore base station antennas. Base stations 105 described herein mayinclude or may be referred to by those skilled in the art as a basetransceiver station, a radio base station, an access point, a radiotransceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB orgiga-NodeB (either of which may be referred to as a gNB), a Home NodeB,a Home eNodeB, or some other suitable terminology. Wirelesscommunications system 100 may include base stations 105 of differenttypes (for example, macro or small cell base stations). The UEs 115described herein may be able to communicate with various types of basestations 105 and network equipment including macro eNBs, small celleNBs, gNBs, relay base stations, and the like.

Each base station 105 may be associated with a particular geographiccoverage area 110 in which communications with various UEs 115 aresupported. Each base station 105 may provide communication coverage fora respective geographic coverage area 110 via communication links 125,and communication links 125 between a base station 105 and a UE 115 mayutilize one or more carriers. Communication links 125 shown in wirelesscommunications system 100 may include uplink transmissions from a UE 115to a base station 105, or downlink transmissions from a base station 105to a UE 115. Downlink transmissions may also be called forward linktransmissions while uplink transmissions may also be called reverse linktransmissions.

The geographic coverage area 110 for a base station 105 may be dividedinto sectors making up a portion of the geographic coverage area 110,and each sector may be associated with a cell. For example, each basestation 105 may provide communication coverage for a macro cell, a smallcell, a hot spot, or other types of cells, or various combinationsthereof. In some examples, a base station 105 may be movable andtherefore provide communication coverage for a moving geographiccoverage area 110. In some examples, different geographic coverage areas110 associated with different technologies may overlap, and overlappinggeographic coverage areas 110 associated with different technologies maybe supported by the same base station 105 or by different base stations105. The wireless communications system 100 may include, for example, aheterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different typesof base stations 105 provide coverage for various geographic coverageareas 110.

The term “cell” refers to a logical communication entity used forcommunication with a base station 105 (for example, over a carrier), andmay be associated with an identifier for distinguishing neighboringcells (for example, a physical cell identifier (PCID), a virtual cellidentifier (VCID)) operating via the same or a different carrier. Insome examples, a carrier may support multiple cells, and different cellsmay be configured according to different protocol types (for example,machine-type communication (MTC), narrowband Internet-of-Things(NB-IoT), enhanced mobile broadband (eMBB), or others) that may provideaccess for different types of devices. In some examples, the term “cell”may refer to a portion of a geographic coverage area 110 (for example, asector) over which the logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system100, and each UE 115 may be stationary or mobile. A UE 115 may also bereferred to as a mobile device, a wireless device, a remote device, ahandheld device, or a subscriber device, or some other suitableterminology, where the “device” may also be referred to as a unit, astation, a terminal, or a client. A UE 115 may also be a personalelectronic device such as a cellular phone, a personal digital assistant(PDA), a tablet computer, a laptop computer, or a personal computer. Insome examples, a UE 115 may also refer to a wireless local loop (WLL)station, an Internet of Things (IoT) device, an Internet of Everything(IoE) device, or an MTC device, or the like, which may be implemented invarious articles such as appliances, vehicles, meters, or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or lowcomplexity devices, and may provide for automated communication betweenmachines (for example, via Machine-to-Machine (M2M) communication). M2Mcommunication or MTC may refer to data communication technologies thatallow devices to communicate with one another or a base station 105without human intervention. In some examples, M2M communication or MTCmay include communications from devices that integrate sensors or metersto measure or capture information and relay that information to acentral server or application program that can make use of theinformation or present the information to humans interacting with theprogram or application. Some UEs 115 may be designed to collectinformation or enable automated behavior of machines. Examples ofapplications for MTC devices include smart metering, inventorymonitoring, water level monitoring, equipment monitoring, healthcaremonitoring, wildlife monitoring, weather and geological eventmonitoring, fleet management and tracking, remote security sensing,physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reducepower consumption, such as half-duplex communications (for example, amode that supports one-way communication via transmission or reception,but not transmission and reception simultaneously). In some exampleshalf-duplex communications may be performed at a reduced peak rate.Other power conservation techniques for UEs 115 include entering a powersaving “deep sleep” mode when not engaging in active communications, oroperating over a limited bandwidth (for example, according to narrowbandcommunications). In some examples, UEs 115 may be designed to supportcritical functions (for example, mission critical functions), and awireless communications system 100 may be configured to provideultra-reliable communications for these functions.

In some examples, a UE 115 may also be able to communicate directly withother UEs 115 (for example, using a peer-to-peer (P2P) ordevice-to-device (D2D) protocol). One or more of a group of UEs 115utilizing D2D communications may be within the geographic coverage area110 of a base station 105. Other UEs 115 in such a group may be outsidethe geographic coverage area 110 of a base station 105, or be otherwiseunable to receive transmissions from a base station 105. In someexamples, groups of UEs 115 communicating via D2D communications mayutilize a one-to-many (1:M) system in which each UE 115 transmits toevery other UE 115 in the group. In some examples, a base station 105facilitates the scheduling of resources for D2D communications. In othercases, D2D communications are carried out between UEs 115 without theinvolvement of a base station 105.

Base stations 105 may communicate with the core network 130 and with oneanother. For example, base stations 105 may interface with the corenetwork 130 through backhaul links 132 (for example, via an S1, N2, N3,or other interface). Base stations 105 may communicate with one anotherover backhaul links 134 (for example, via an X2, Xn, or other interface)either directly (for example, directly between base stations 105) orindirectly (for example, via core network 130).

The core network 130 may provide user authentication, accessauthorization, tracking, Internet Protocol (IP) connectivity, and otheraccess, routing, or mobility functions. The core network 130 may be anevolved packet core (EPC), which may include at least one mobilitymanagement entity (MME), at least one serving gateway (S-GW), and atleast one Packet Data Network (PDN) gateway (P-GW). The MME may managenon-access stratum (for example, control plane) functions such asmobility, authentication, and bearer management for UEs 115 served bybase stations 105 associated with the EPC. User IP packets may betransferred through the S-GW, which itself may be connected to the P-GW.The P-GW may provide IP address allocation as well as other functions.The P-GW may be connected to the network operators IP services. Theoperators IP services may include access to the Internet, Intranet(s),an IP Multimedia Subsystem (IMS), or a Packet-Switched (PS) StreamingService.

At least some of the network devices, such as a base station 105, mayinclude subcomponents such as an access network entity, which may be anexample of an access node controller (ANC). Each access network entitymay communicate with UEs 115 through a number of other access networktransmission entities, which may be referred to as a radio head, a smartradio head, or a transmission/reception point (TRP). In someconfigurations, various functions of each access network entity or basestation 105 may be distributed across various network devices (forexample, radio heads and access network controllers) or consolidatedinto a single network device (for example, a base station 105).

Wireless communications system 100 may operate using one or morefrequency bands, typically in the range of 300 megahertz (MHz) to 300gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known asthe ultra-high frequency (UHF) region or decimeter band, because thewavelengths range from approximately one decimeter to one meter inlength. UHF waves may be blocked or redirected by buildings andenvironmental features. However, the waves may penetrate structuressufficiently for a macro cell to provide service to UEs 115 locatedindoors. Transmission of UHF waves may be associated with smallerantennas and shorter range (for example, less than 100 km) compared totransmission using the smaller frequencies and longer waves of the highfrequency (HF) or very high frequency (VHF) portion of the spectrumbelow 300 MHz.

Wireless communications system 100 may also operate in a super highfrequency (SHF) region using frequency bands from 3 GHz to 30 GHz, alsoknown as the centimeter band. The SHF region includes bands such as the5 GHz industrial, scientific, and medical (ISM) bands, which may be usedopportunistically by devices that may be capable of toleratinginterference from other users.

Wireless communications system 100 may also operate in an extremely highfrequency (EHF) region of the spectrum (for example, from 30 GHz to 300GHz), also known as the millimeter band. In some examples, wirelesscommunications system 100 may support millimeter wave (mmW)communications between UEs 115 and base stations 105, and EHF antennasof the respective devices may be even smaller and more closely spacedthan UHF antennas. In some examples, this may facilitate use of antennaarrays within a UE 115. However, the propagation of EHF transmissionsmay be subject to even greater atmospheric attenuation and shorter rangethan SHF or UHF transmissions. Techniques disclosed herein may beemployed across transmissions that use one or more different frequencyregions, and designated use of bands across these frequency regions maydiffer by country or regulating body.

In some examples, wireless communications system 100 may utilize bothlicensed and unlicensed radio frequency spectrum bands. For example,wireless communications system 100 may employ License Assisted Access(LAA), LTE-Unlicensed (LTE-U) radio access technology, or NR technologyin an unlicensed band such as the 5 GHz ISM band. When operating inunlicensed radio frequency spectrum bands, wireless devices such as basestations 105 and UEs 115 may employ listen-before-talk (LBT) proceduresto ensure a frequency channel is clear before transmitting data. In someexamples, operations in unlicensed bands may be based on a carrieraggregation configuration in conjunction with component carriersoperating in a licensed band (for example, LAA). Operations inunlicensed spectrum may include downlink transmissions, uplinktransmissions, peer-to-peer transmissions, or a combination of these.Duplexing in unlicensed spectrum may be based on frequency divisionduplexing (FDD), time division duplexing (TDD), or a combination ofboth.

In some examples, base station 105 or UE 115 may be equipped withmultiple antennas, which may be used to employ techniques such astransmit diversity, receive diversity, multiple-input multiple-output(MIMO) communications, or beamforming. For example, wirelesscommunications system 100 may use a transmission scheme between atransmitting device (for example, a base station 105) and a receivingdevice (for example, a UE 115), where the transmitting device isequipped with multiple antennas and the receiving device is equippedwith one or more antennas. MIMO communications may employ multipathsignal propagation to increase the spectral efficiency by transmittingor receiving multiple signals via different spatial layers, which may bereferred to as spatial multiplexing. The multiple signals may, forexample, be transmitted by the transmitting device via differentantennas or different combinations of antennas. Likewise, the multiplesignals may be received by the receiving device via different antennasor different combinations of antennas. Each of the multiple signals maybe referred to as a separate spatial stream, and may carry bitsassociated with the same data stream (for example, the same codeword) ordifferent data streams. Different spatial layers may be associated withdifferent antenna ports used for channel measurement and reporting. MIMOtechniques include single-user MIMO (SU-MIMO) where multiple spatiallayers are transmitted to the same receiving device, and multiple-userMIMO (MU-MIMO) where multiple spatial layers are transmitted to multipledevices.

Beamforming, which may also be referred to as spatial filtering,directional transmission, or directional reception, is a signalprocessing technique that may be used at a transmitting device or areceiving device (for example, a base station 105 or a UE 115) to shapeor steer an antenna beam (for example, a transmit beam or receive beam)along a spatial path between the transmitting device and the receivingdevice. Beamforming may be achieved by combining the signalscommunicated via antenna elements of an antenna array such that signalspropagating at particular orientations with respect to an antenna arrayexperience constructive interference while others experience destructiveinterference. The adjustment of signals communicated via the antennaelements may include a transmitting device or a receiving deviceapplying amplitude and phase offsets to signals carried via each of theantenna elements associated with the device. The adjustments associatedwith each of the antenna elements may be defined by a beamforming weightset associated with a particular orientation (for example, with respectto the antenna array of the transmitting device or receiving device, orwith respect to some other orientation).

In one example, a base station 105 may use multiple antennas or antennaarrays to conduct beamforming operations for directional communicationswith a UE 115. For instance, some signals (for example synchronizationsignals, reference signals, beam selection signals, or other controlsignals) may be transmitted by a base station 105 multiple times indifferent directions, which may include a signal being transmittedaccording to different beamforming weight sets associated with differentdirections of transmission. Transmissions in different beam directionsmay be used to identify (for example, by the base station 105 or areceiving device, such as a UE 115) a beam direction for subsequenttransmission or reception by the base station 105.

Some signals, such as data signals associated with a particularreceiving device, may be transmitted by a base station 105 in a singlebeam direction (for example, a direction associated with the receivingdevice, such as a UE 115). In some examples, the beam directionassociated with transmissions along a single beam direction may bedetermined based on a signal that was transmitted in different beamdirections. For example, a UE 115 may receive one or more of the signalstransmitted by the base station 105 in different directions, and the UE115 may report to the base station 105 an indication of the signal itreceived with a highest signal quality, or an otherwise acceptablesignal quality. Although these techniques are described with referenceto signals transmitted in one or more directions by a base station 105,a UE 115 may employ similar techniques for transmitting signals multipletimes in different directions (for example, for identifying a beamdirection for subsequent transmission or reception by the UE 115), ortransmitting a signal in a single direction (for example, fortransmitting data to a receiving device).

A receiving device (for example, a UE 115, which may be an example of ammW receiving device) may try multiple receive beams when receivingvarious signals from the base station 105, such as synchronizationsignals, reference signals, beam selection signals, or other controlsignals. For example, a receiving device may try multiple receivedirections by receiving via different antenna subarrays, by processingreceived signals according to different antenna subarrays, by receivingaccording to different receive beamforming weight sets applied tosignals received at a plurality of antenna elements of an antenna array,or by processing received signals according to different receivebeamforming weight sets applied to signals received at a plurality ofantenna elements of an antenna array, any of which may be referred to as“listening” according to different receive beams or receive directions.In some examples a receiving device may use a single receive beam toreceive along a single beam direction (for example, when receiving adata signal). The single receive beam may be aligned in a beam directiondetermined based on listening according to different receive beamdirections (for example, a beam direction determined to have a highestsignal strength, highest signal-to-noise ratio, or otherwise acceptablesignal quality based on listening according to multiple beamdirections).

In some examples, the antennas of a base station 105 or UE 115 may belocated within one or more antenna arrays, which may support MIMOoperations, or transmit or receive beamforming. For example, one or morebase station antennas or antenna arrays may be co-located at an antennaassembly, such as an antenna tower. In some examples, antennas orantenna arrays associated with a base station 105 may be located indiverse geographic locations. A base station 105 may have an antennaarray with a number of rows and columns of antenna ports that the basestation 105 may use to support beamforming of communications with a UE115. Likewise, a UE 115 may have one or more antenna arrays that maysupport various MIMO or beamforming operations.

In some examples, wireless communications system 100 may be apacket-based network that operates according to a layered protocolstack. In the user plane, communications at the bearer or Packet DataConvergence Protocol (PDCP) layer may be IP-based. A Radio Link Control(RLC) layer may perform packet segmentation and reassembly tocommunicate over logical channels. A Medium Access Control (MAC) layermay perform priority handling and multiplexing of logical channels intotransport channels. The MAC layer may also use hybrid automatic repeatrequest (HARQ) to provide retransmission at the MAC layer to improvelink efficiency. In the control plane, the Radio Resource Control (RRC)protocol layer may provide establishment, configuration, and maintenanceof an RRC connection between a UE 115 and a base station 105 or corenetwork 130 supporting radio bearers for user plane data. At thePhysical layer, transport channels may be mapped to physical channels.

In some examples, UEs 115 and base stations 105 may supportretransmissions of data to increase the likelihood that data is receivedsuccessfully. HARQ feedback is one technique of increasing thelikelihood that data is received correctly over a communication link125. HARQ may include a combination of error detection (for example,using a cyclic redundancy check (CRC)), forward error correction (FEC),and retransmission (for example, automatic repeat request (ARQ)). HARQmay improve throughput at the MAC layer in poor radio conditions (forexample, signal-to-noise conditions). In some examples, a wirelessdevice may support same-slot HARQ feedback, where the device may provideHARQ feedback in a specific slot for data received in a previous symbolin the slot. In other cases, the device may provide HARQ feedback in asubsequent slot, or according to some other time interval.

Time intervals in LTE or NR may be expressed in multiples of a basictime unit, which may, for example, refer to a sampling duration ofT_(s)= 1/30,720,000 seconds. Time intervals of a communications resourcemay be organized according to radio frames each having a duration of 10milliseconds (ms), where the frame duration may be expressed asT_(f)=307,200 T_(s). The radio frames may be identified by a systemframe number (SFN) ranging from 0 to 1023. Each frame may include 10subframes numbered from 0 to 9, and each subframe may have a duration of1 ms. A subframe may be further divided into 2 slots each having aduration of 0.5 ms, and each slot may contain 6 or 7 modulation symbolperiods (for example, depending on the length of the cyclic prefixprepended to each symbol period). Excluding the cyclic prefix, eachsymbol duration may contain 2048 sampling periods. In some examples, asubframe may be the smallest scheduling unit of the wirelesscommunications system 100, and may be referred to as a transmission timeinterval (TTI). In other cases, a smallest scheduling unit of thewireless communications system 100 may be shorter than a subframe or maybe dynamically selected (for example, in bursts of shortened TTIs(sTTIs) or in selected component carriers using sTTIs).

In some wireless communications systems, a slot may further be dividedinto multiple mini-slots containing one or more symbols. In someinstances, a symbol of a mini-slot or a mini-slot may be the smallestunit of scheduling. Each symbol may vary in duration depending on thesubcarrier spacing or frequency band of operation, for example. Further,some wireless communications systems may implement slot aggregation inwhich multiple slots or mini-slots are aggregated together and used forcommunication between a UE 115 and a base station 105.

The term “carrier” refers to a set of radio frequency spectrum resourceshaving a defined physical layer structure for supporting communicationsover a communication link 125. For example, a carrier of a communicationlink 125 may include a portion of a radio frequency spectrum band thatis operated according to physical layer channels for a given radioaccess technology. Each physical layer channel may carry user data,control information, or other signaling. A carrier may be associatedwith a pre-defined frequency channel (for example, an evolved universalmobile telecommunication system terrestrial radio access (E-UTRA)absolute radio frequency channel number (EARFCN)), and may be positionedaccording to a channel raster for discovery by UEs 115. Carriers may bedownlink or uplink (for example, in an FDD mode), or be configured tocarry downlink and uplink communications (for example, in a TDD mode).In some examples, signal waveforms transmitted over a carrier may bemade up of multiple sub-carriers (for example, using multi-carriermodulation (MCM) techniques such as orthogonal frequency divisionmultiplexing (OFDM) or discrete Fourier transform spread OFDM(DFT-S-OFDM)).

The organizational structure of the carriers may be different fordifferent radio access technologies (for example, LTE, LTE-A, LTE-A Pro,NR). For example, communications over a carrier may be organizedaccording to TTIs or slots, each of which may include user data as wellas control information or signaling to support decoding the user data. Acarrier may also include dedicated acquisition signaling (for example,synchronization signals or system information, etc.) and controlsignaling that coordinates operation for the carrier. In some examples(for example, in a carrier aggregation configuration), a carrier mayalso have acquisition signaling or control signaling that coordinatesoperations for other carriers.

Physical channels may be multiplexed on a carrier according to varioustechniques. A physical control channel and a physical data channel maybe multiplexed on a downlink carrier, for example, using time divisionmultiplexing (TDM) techniques, frequency division multiplexing (FDM)techniques, or hybrid TDM-FDM techniques. In some examples, controlinformation transmitted in a physical control channel may be distributedbetween different control regions in a cascaded manner (for example,between a common control region or common search space and one or moreUE-specific control regions or UE-specific search spaces).

A carrier may be associated with a particular bandwidth of the radiofrequency spectrum, and in some examples the carrier bandwidth may bereferred to as a “system bandwidth” of the carrier or the wirelesscommunications system 100. For example, the carrier bandwidth may be oneof a number of determined bandwidths for carriers of a particular radioaccess technology (for example, 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz).In some examples, each served UE 115 may be configured for operatingover portions or all of the carrier bandwidth. In other examples, someUEs 115 may be configured for operation using a narrowband protocol typethat is associated with a defined portion or range (for example, set ofsubcarriers or RBs) within a carrier (for example, “in-band” deploymentof a narrowband protocol type).

In a system employing MCM techniques, a resource element may consist ofone symbol duration (for example, a duration of one modulation symbol)and one subcarrier, where the symbol duration and subcarrier spacing areinversely related. The number of bits carried by each resource elementmay depend on the modulation scheme (for example, the order of themodulation scheme). Thus, the more resource elements that a UE 115receives and the higher the order of the modulation scheme, the higherthe data rate may be for the UE 115. In MIMO systems, a wirelesscommunications resource may refer to a combination of a radio frequencyspectrum resource, a time resource, and a spatial resource (for example,spatial layers), and the use of multiple spatial layers may furtherincrease the data rate for communications with a UE 115.

Devices of the wireless communications system 100 (for example, basestations 105 or UEs 115) may have a hardware configuration that supportscommunications over a particular carrier bandwidth, or may beconfigurable to support communications over one of a set of carrierbandwidths. In some examples, the wireless communications system 100 mayinclude base stations 105 or UEs 115 that support simultaneouscommunications via carriers associated with more than one differentcarrier bandwidth.

Wireless communications system 100 may support communication with a UE115 on multiple cells or carriers, a feature which may be referred to ascarrier aggregation or multi-carrier operation. A UE 115 may beconfigured with multiple downlink component carriers and one or moreuplink component carriers according to a carrier aggregationconfiguration. Carrier aggregation may be used with both FDD and TDDcomponent carriers.

In some examples, wireless communications system 100 may utilizeenhanced component carriers (eCCs). An eCC may be characterized by oneor more features including wider carrier or frequency channel bandwidth,shorter symbol duration, shorter TTI duration, or modified controlchannel configuration. In some examples, an eCC may be associated with acarrier aggregation configuration or a dual connectivity configuration(for example, when multiple serving cells have a suboptimal or non-idealbackhaul link). An eCC may also be configured for use in unlicensedspectrum or shared spectrum (for example, where more than one operatoris allowed to use the spectrum). An eCC characterized by wide carrierbandwidth may include one or more segments that may be utilized by UEs115 that are not capable of monitoring the whole carrier bandwidth orare otherwise configured to use a limited carrier bandwidth (forexample, to conserve power).

In some examples, an eCC may utilize a different symbol duration thanother component carriers, which may include use of a reduced symbolduration as compared with symbol durations of the other componentcarriers. A shorter symbol duration may be associated with increasedspacing between adjacent subcarriers. A device, such as a UE 115 or basestation 105, utilizing eCCs may transmit wideband signals (for example,according to frequency channel or carrier bandwidths of 20, 40, 60, 80MHz, etc.) at reduced symbol durations (for example, 16.67microseconds). A TTI in eCC may consist of one or multiple symbolperiods. In some examples, the TTI duration (that is, the number ofsymbol periods in a TTI) may be variable.

Wireless communications system 100 may be an NR system that may utilizeany combination of licensed, shared, and unlicensed spectrum bands,among others. The flexibility of eCC symbol duration and subcarrierspacing may allow for the use of eCC across multiple spectrums. In someexamples, NR shared spectrum may increase spectrum utilization andspectral efficiency, specifically through dynamic vertical (for example,across the frequency domain) and horizontal (for example, across thetime domain) sharing of resources.

As described herein, wireless communications system 100 may be an NRsystem and support communications between the one or more base stations105 and supported UEs 115 using communication links 125. The UEs 115 maybe dispersed throughout the wireless communications system 100, and eachUE 115 may be stationary or mobile. Wireless communications system 100may minimize always-on transmission and support forward capability,including transmission of reference signals based on a need at a basestation 105 or a UE 115. As part of the communication, each of the basestations 105 and UEs 115 may support reference signal transmission foroperations, including channel estimation, beam management andscheduling, and wireless device positioning within the one or morecoverage areas 110.

For example, the base stations 105 may transmit one or more downlinkreference signals for NR communications, including channel stateinformation reference signal (CSI-RS) transmission. Each of the CSI-RStransmissions may be configured for a specific UE 115 to estimate thechannel and report channel quality information. The reported channelquality information may be used for scheduling or link adaptation at thebase stations 105, or as part of a mobility or beam management procedurefor directional transmission associated with the enhanced channelresources.

A base station 105 may configure a CSI-RS transmission on one or moreCSI-RS resources of the channel. A CSI-RS resource may start at any OFDMsymbol of a slot and occupy one or more symbols depending on aconfigured number of ports. For example, a CSI-RS resource may span onesymbol of a slot and contain one port for transmission. The one or moreCSI-RS resources may span a number of CSI-RS resource sets configuredaccording to a CSI-RS resource setting of the base station 105. Thestructure of the one or more CSI-RS resources, CSI-RS resource sets, andCSI-RS resource settings within a CSI-RS transmission may be referred toas a multi-level resource setting. For example, a multi-level CSI-RSresource setting of the base station 105 may include up to 16 CSI-RSresource sets and each CSI-RS resource set may contain up to 64 CSI-RSresources. In some examples, the base station 105 may support aconfigured number of distinct CSI-RS resources (for example, 128) overone or more CSI-RS resource sets.

In some examples, a base station 105 may provide an indication (such asthe tag “Repetition=ON”) associated with a CSI-RS transmission directedto a UE 115. The indication may define whether the UE 115 may assume theincluded CSI-RS resources within the reference signal (for example, anon-zero power (NZP) CSI-RS transmission) are associated with the samedownlink spatial domain transmission filter and correspond to a singletransmit beam at the base station 105. The indication may be configuredaccording to a higher layer signaling parameter (for example,reportQuantity) associated with all the reporting settings linked withthe CSI-RS resource set. For example, the base station 105 may configurethe reportQuantity parameter to a set indication (for example“cri-RSRP”, “none”, etc.) that indicates a single transmit beam.

At reception, the UE 115 may identify the configured set indicationassociated with the received higher layer signaling parameter. In someexamples (such as “cri-RSRP” reporting), the UE 115 may determine CSIparameters for the one or more CSI-RS resources and report themeasurements according to a refined reporting configuration. Forexample, the UE 115 may determine CSI parameters (for example, RSRPvalues) for the one or more channel resources. The UE 115 may thencondition the reporting according to a configured channel resourceindicator (CRI) value, as one example, where the CRI value correspondsto an index of a resource entry associated with the one or more CSI-RSresources in a corresponding CSI-RS resource set for channelmeasurement.

In some examples, the base stations 105 may transmit one or moreadditional downlink reference signals for communication, including apositioning reference signal (PRS) transmission. The PRS transmissionmay be configured for a specific UE 115 to measure and report one ormore report parameters (for example, report quantities) associated withpositioning and location information. A base station 105 may use thereported information as part of a UE-assisted positioning technique. ThePRS transmission and report parameter feedback may support variouslocation services (for example, navigation systems, emergencycommunications). In some examples, the report parameters supplement oneor more additional location systems supported by the UE 115 (such asglobal positioning system (GPS) technology).

A base station 105 may configure a PRS transmission on one or more PRSresources of a channel. A PRS resource may span resource elements ofmultiple physical resource blocks (PRBs) within one or more OFDM symbolsof a slot depending on a configured number of ports. For example, a PRSresource may span one symbol of a slot and contain one port fortransmission. In any OFDM symbol, the PRS resources may occupyconsecutive PRBs. In some examples, the PRS transmission may be mappedto consecutive OFDM symbols of the slot. In other examples, the PRStransmission may be mapped to interspersed OFDM symbols of the slot.Additionally, the PRS transmission may support frequency hopping withinPRBs of the channel.

The one or more PRS resources may span a number of PRS resource setsaccording to a PRS resource setting of the base station 105. Thestructure of the one or more PRS resources, PRS resource sets, and PRSresource settings within a PRS transmission may be referred to as amulti-level resource setting. For example, multi-level PRS resourcesetting of the base station 105 may include multiple PRS resource setsand each PRS resource set may contain a set of PRS resources (such as aset of 4 PRS resources).

The UE 115 may receive the PRS transmission over the one or more PRSresources of the slot. The UE 115 may determine a report parameter forat least some of if not each PRS resource included in the transmission.The report parameter (which may include a report quantity) for each PRSresource may include one or more of a time of arrival (TOA), a referencesignal time difference (RSTD), a reference signal receive power (RSRP),an angle, a PRS identification number, a reception to transmissiondifference (UE Rx−Tx), a signal-to-noise ratio (SNR), or a referencesignal receive quality (RSRQ).

Wireless communications system 100 may be or include a multicarrierbeamformed communication system, such as a mmW wireless communicationsystem. Aspects of wireless communications system 100 may include use ofPRS transmissions by the base station 105 or sounding reference signal(SRS) transmissions by the UE 115 for UE location determination. Fordownlink-based UE location determination, a positioning engine 101,e.g., a location server such as a Location Management Function (LMF) ina NR network or a Secure User Plane Location (SUPL) Location Platform(SLP) in LTE, may be used to provide PRS assistance data (AD) to the UE115. In UE-assisted positioning, the positioning engine may receivemeasurement reports from the UE 115 that indicates position measurementsfor one or multiple base stations 105 with which positioning engine maydetermine a position estimate for the UE 115, e.g., using OTDOA, orother desired techniques. The positioning engine 101 is illustrated inFIG. 1 as being located at a base station 105, but may be locatedelsewhere, e.g., within the core network 130.

For uplink-based UE location determination, the base station 105 mayreceive SRS transmissions from the UE 1150 and determine positionmeasurements, such as TOA or Rx−Tx. A positioning engine 101 may receivemeasurement reports from one or more base stations 105 with the positionmeasurements and may determine a position estimate for the UE 115, e.g.,using OTDOA or other desired techniques.

Additionally, RAT independent techniques may be used to estimate aposition of the UE 115. For example, the communications system 100 mayfurther utilize information from space vehicles (SVs) (not illustrated)for a Global Navigation Satellite System (GNSS) like GPS, GLONASS,Galileo or Beidou or some other local or regional Satellite PositioningSystem (SPS) such as IRNSS, EGNOS or WAAS. Location related measurementsobtained by UE 115 may include measurements of signals received from theSVs and/or may include measurements of signals received from terrestrialtransmitters fixed at known locations (e.g., such as base stations 105).The UE 115 or positioning engine 101 to which UE 115 may send themeasurements, may then obtain a location estimate for the UE 115 basedon these location related measurements using any one of several positionmethods such as, for example, GNSS, Assisted GNSS (A-GNSS), AdvancedForward Link Trilateration (AFLT), Observed Time Difference Of Arrival(OTDOA), WLAN (also referred to as WiFi) positioning, or Enhanced CellID (ECID) or combinations thereof. In some of these techniques (e.g.A-GNSS, AFLT and OTDOA), pseudoranges or timing differences may bemeasured at UE 115 relative to three or more terrestrial transmitters(e.g. base stations 105) fixed at known locations or relative to four ormore SVs with accurately known orbital data, or combinations thereof,based at least in part, on pilots, positioning reference signals (PRS)or other positioning related signals transmitted by the transmitters orsatellites and received at the UE 115.

FIG. 2 shows a structure of an example subframe sequence 200 with PRSpositioning occasions. Subframe sequence 200 may be applicable tobroadcast of PRS signals from base stations 105 in communication systems100. While FIG. 2 provides an example of a subframe sequence for LTE,similar subframe sequence implementations may be realized for othercommunication technologies/protocols, such as 5G and NR. In FIG. 2, timeis represented horizontally (e.g., on an X axis) with time increasingfrom left to right, while frequency is represented vertically (e.g., ona Y axis) with frequency increasing (or decreasing) from bottom to top.As shown in FIG. 2, downlink and uplink Radio Frames 210 may be of 10 msduration each. For downlink Frequency Division Duplex (FDD) mode, RadioFrames 210 are organized, in the illustrated embodiments, into tensubframes 212 of 1 ms duration each. Each subframe 212 comprises twoslots 214, each of, for example, 0.5 ms duration.

In the frequency domain, the available bandwidth may be divided intouniformly spaced orthogonal subcarriers 216. For example, for a normallength cyclic prefix using, for example, 15 kHz spacing, subcarriers 216may be grouped into a group of twelve (12) subcarriers. Each grouping,which comprises the 12 subcarriers 216, is termed a resource block and,in the example above, the number of subcarriers in the resource blockmay be written as N_(SC) ^(RB)=12. For a given channel bandwidth, thenumber of available resource blocks on each channel 222, which is alsocalled the transmission bandwidth configuration 222, is indicated asN_(RB) ^(DL). For example, for a 3 MHz channel bandwidth in the aboveexample, the number of available resource blocks on each channel 222 isgiven by N_(RB) ^(DL)=15.

In the communication system 100 illustrated in FIG. 1, a base station105, such as macro cell base station or any of small cell base stations,may transmit frames, or other physical layer signaling sequences,supporting PRS signals (i.e. a downlink (DL) PRS) according to frameconfigurations either similar to, or the same as that, shown in FIG. 2and (as described later) in FIG. 3, which may be measured and used forUE (e.g., UE 115) position determination. As noted, other types ofwireless nodes and base stations (e.g., a gNB or WiFi AP) may also beconfigured to transmit PRS signals configured in a manner similar to (orthe same as) that depicted in FIGS. 2 and 3. Since transmission of a PRSby a wireless node or base station is directed to all UEs within radiorange, a wireless node or base station can also be considered totransmit (or broadcast) a PRS.

A PRS, which has been defined in Third Generation Partnership Project(3GPP) LTE Release-9 and later releases, may be transmitted by wirelessnodes (e.g., base stations 105) after appropriate configuration (e.g.,by an Operations and Maintenance (O&M) server). A PRS may be transmittedin special positioning subframes that are grouped into positioningoccasions. PRS occasions may be grouped into one or more PRS occasiongroups. For example, in LTE, a PRS positioning occasion can comprise anumber N_(PRS) of consecutive positioning subframes where the numberN_(PRS) may be between 1 and 160 (e.g., may include the values 1, 2, 4and 6 as well as other values). The PRS positioning occasions for a cellsupported by a wireless node may occur periodically at intervals,denoted by a number T_(PRS), of millisecond (or subframe) intervalswhere T_(PRS) may equal 5, 10, 20, 40, 80, 160, 320, 640, or 1280 (orany other appropriate value). As an example, FIG. 2 illustrates aperiodicity of positioning occasions where N_(PRS) equals 4 218 andT_(PRS) is greater than or equal to 20 220. In some aspects, T_(PRS) maybe measured in terms of the number of subframes between the start ofconsecutive positioning occasions.

As discussed herein, in some aspects, OTDOA assistance data may beprovided to a UE 115 by a location server, e.g., positioning engine 101for a “reference cell” and one or more “neighbor cells” or “neighboringcells” relative to the “reference cell.” For example, the assistancedata may provide the center channel frequency of each cell, various PRSconfiguration parameters (e.g., N_(PRS), T_(PRS), muting sequence,frequency hopping sequence, PRS ID, PRS bandwidth), a cell global ID,PRS signal characteristics associated with a directional PRS, and/orother cell related parameters applicable to OTDOA or some other positionmethod.

PRS-based positioning by a UE 115 may be facilitated by indicating theserving cell for the UE 115 in the OTDOA assistance data (e.g., with thereference cell indicated as being the serving cell).

In some aspects, OTDOA assistance data may also include “expected RSTD”parameters, which provide the UE 115 with information about the RSTDvalues the UE 115 is expected to measure at its current location betweenthe reference cell and each neighbor cell, together with an uncertaintyof the expected RSTD parameter. The expected RSTD, together with theassociated uncertainty, may define a search window for the UE 115 withinwhich the UE 115 is expected to measure the RSTD value. OTDOA assistanceinformation may also include PRS configuration information parameters,which allow a UE 115 to determine when a PRS positioning occasion occurson signals received from various neighbor cells relative to PRSpositioning occasions for the reference cell, and to determine the PRSsequence transmitted from various cells in order to measure a signalTime of Arrival (ToA) or RSTD.

Using the RSTD measurements, the known absolute or relative transmissiontiming of each cell, and the known position(s) of wireless node physicaltransmitting antennas for the reference and neighboring cells, the UE115's position may be calculated (e.g., by the UE 115 or by thepositioning engine 101). More particularly, the RSTD for a neighbor cell“k” relative to a reference cell “Ref,” may be given as(ToA_(k)−ToA_(Ref)), where the ToA values may be measured modulo onesubframe duration (1 ms) to remove the effects of measuring differentsubframes at different times. ToA measurements for different cells maythen be converted to RSTD measurements (e.g., as defined in 3GPPTechnical Specification (TS) 36.214 entitled “Physical layer;Measurements”) and sent to the positioning engine 101 by the UE 115.Using (i) the RSTD measurements, (ii) the known absolute or relativetransmission timing of each cell. (iii) the known position(s) ofphysical transmitting antennas for the reference and neighboring cells,and/or (iv) directional PRS characteristics such as a direction oftransmission, the UE 115's position may be determined.

FIG. 3 illustrates an exemplary PRS configuration 300 for a cellsupported by a wireless node (such as a base station 105). Again, PRStransmission for LTE is assumed in FIG. 3, although the same or similaraspects of PRS transmission to those shown in and described for FIG. 3may apply to 5G, NR, and/or other wireless technologies. FIG. 3 showshow PRS positioning occasions are determined by a System Frame Number(SFN), a cell specific subframe offset (Δ_(PRS)) 352, and the PRSPeriodicity (T_(PRS)) 320. Typically, the cell specific PRS subframeconfiguration is defined by a “PRS Configuration Index” I_(PRS) includedin the OTDOA assistance data. The PRS Periodicity (T_(PRS)) 320 and thecell specific subframe offset (Δ_(PRS)) are defined based on the PRSConfiguration Index I_(PRS), in 3GPP TS 36.211 entitled “Physicalchannels and modulation,” as illustrated in Table 1 below.

TABLE 1 PRS configuration PRS periodicity PRS subframe offset IndexI_(PRS) T_(PRS) (subframes) Δ_(PRS) (subframes)  0-159 160 I_(PRS)160-479 320 I_(PRS) − 160  480-1119 640 I_(PRS) − 480 1120-2399 1280I_(PRS) − 1120 2400-2404 5 I_(PRS) − 2400 2405-2414 10 I_(PRS) − 24052415-2434 20 I_(PRS) − 2415 2435-2474 40 I_(PRS) − 2435 2475-2554 80I_(PRS) − 2475 2555-4095 Reserved

A PRS configuration is defined with reference to the System Frame Number(SFN) of a cell that transmits PRS. PRS instances, for the firstsubframe of the N_(PRS) downlink subframes comprising a first PRSpositioning occasion, may satisfy:(10×n _(f) +└n _(s)/2┘−Δ_(PRS))mod T _(PRS)=0,

where n_(f) is the SFN with 0≤n_(f)≤1023, n_(s) is the slot numberwithin the radio frame defined by n_(f) with 0≤n_(s)≤19, T_(PRS) is thePRS periodicity 320, and Δ_(PRS) is the cell-specific subframe offset352.

As shown in FIG. 3, the cell specific subframe offset Δ_(PRS) 352 may bedefined in terms of the number of subframes transmitted starting fromSystem Frame Number 0 (Slot ‘Number 0’, marked as slot 350) to the startof the first (subsequent) PRS positioning occasion. In the example inFIG. 3, the number of consecutive positioning subframes (N_(PRS)) ineach of the consecutive PRS positioning occasions 318 a, 318 b, and 318c equals 4.

In some aspects, when a UE 115 receives a PRS configuration indexI_(PRS) in the OTDOA assistance data for a particular cell, the UE 115may determine the PRS periodicity T_(PRS) 320 and PRS subframe offsetΔ_(PRS) using Table 1. The UE 115 may then determine the radio frame,subframe and slot when a PRS is scheduled in the cell (e.g., usingequation (1)). The OTDOA assistance data may be determined by, forexample, the positioning engine 101, and includes assistance data for areference cell, and a number of neighbor cells supported by variouswireless nodes.

Typically, PRS occasions from all cells in a network that use the samefrequency are aligned in time and may have a fixed known time offset(e.g., cell-specific subframe offset 352) relative to other cells in thenetwork that use a different frequency. In SFN-synchronous networks allwireless nodes (e.g., base stations 105) may be aligned on both frameboundary and system frame number. Therefore, in SFN-synchronous networksall cells supported by the various wireless nodes may use the same PRSconfiguration index for any particular frequency of PRS transmission. Onthe other hand, in SFN-asynchronous networks, the various wireless nodesmay be aligned on a frame boundary, but not system frame number. Thus,in SFN-asynchronous networks the PRS configuration index for each cellmay be configured separately by the network so that PRS occasions alignin time.

A UE 115 may determine the timing of the PRS occasions of the referenceand neighbor cells for OTDOA positioning, if the UE 115 can obtain thecell timing (e.g., SFN or Frame Number) of at least one of the cells,e.g., the reference cell or a serving cell. The timing of the othercells may then be derived by the UE 115 based, for example, on theassumption that PRS occasions from different cells overlap.

As defined by 3GPP (e.g., in 3GPP TS 36.211), for LTE systems, thesequence of subframes used to transmit PRS (e.g., for OTDOA positioning)may be characterized and defined by a number of parameters, as describedpreviously, comprising: (i) a reserved block of bandwidth (BW), (ii) theconfiguration index I_(PRS), (iii) the duration N_(PRS), (iv) anoptional muting pattern; and (v) a muting sequence periodicity T_(REP)that can be implicitly included as part of the muting pattern in (iv)when present. In some cases, with a fairly low PRS duty cycle,N_(PRS)=1, T_(PRS)=160 subframes (equivalent to 160 ms), and BW=1.4, 3,5, 10, 15, or 20 MHz. To increase the PRS duty cycle, the N_(PRS) valuecan be increased to six (i.e., N_(PRS)=6) and the bandwidth (BW) valuecan be increased to the system bandwidth (i.e., BW=LTE system bandwidthin the case of LTE). An expanded PRS with a larger N_(PRS) (e.g.,greater than six) and/or a shorter T_(PRS) (e.g., less than 160 ms), upto the full duty cycle (i.e., N_(PRS)=T_(PRS)), may also be used inlater versions of LPP according to 3GPP TS 36.355. A directional PRS maybe configured as just described according to 3GPP TSs and may, forexample, use a low PRS duty cycle (e.g., N_(PRS)=1, T_(PRS)=160subframes) or a high duty cycle.

FIG. 4 illustrates an exemplary PRS configuration 400 in LTE thatincludes a PRS muting sequence. Like FIG. 3, FIG. 4 shows how PRSpositioning occasions are determined by an SFN, a cell specific subframeoffset (Δ_(PRS)) 452, and the PRS Periodicity (T_(PRS)) 420. As shown inFIG. 4, the cell specific subframe offset Δ_(PRS) 452 may be defined interms of the number of subframes transmitted starting from System FrameNumber 0 (Slot ‘Number 0’, marked as slot 450) to the start of the first(subsequent) PRS positioning occasion. In the example in FIG. 4, thenumber of consecutive positioning subframes (N_(PRS)) in each of theconsecutive PRS positioning occasions 418 a and 418 b equals 4.

Within each positioning occasion, PRS are generally transmitted with aconstant power. A PRS can also be transmitted with zero power (i.e.,muted). Muting, which turns off a regularly scheduled PRS transmission,may be useful when PRS signals between different cells overlap byoccurring at the same or almost the same time. In this case, the PRSsignals from some cells may be muted while PRS signals from other cellsare transmitted (e.g., at a constant power). Muting may aid signalacquisition and ToA and RSTD measurement, by UEs (such as the UE 115),of PRS signals that are not muted (by avoiding interference from PRSsignals that have been muted). For example, when the (strong) PRS signalthe UE 115 receives from one base station 105 is muted, the (weak) PRSsignals from a neighboring base station 105 can be more easily detectedby the UE 115. Muting may be viewed as the non-transmission of a PRS fora given positioning occasion for a particular cell. Muting patterns(also referred to as muting sequences) may be signaled to a UE 115 usingbit strings. For example, in a bit string signaled to indicate a mutingpattern, if a bit at position j is set to ‘0’, then the UE 115 may inferthat the PRS is muted for j^(th) positioning occasion.

With reference to FIG. 4, the muting sequence periodicity TRP 430includes two consecutive PRS positioning occasions 418 a and 418 bfollowed by two consecutive muted PRS positioning occasions 418 c and418 d. In LTE, the PRS muting configuration of a cell is only defined bya periodic muting sequence (e.g., muting sequence periodicity T_(REP)430), as opposed to an aperiodic or semi-persistent muting sequence. Assuch, the two consecutive PRS positioning occasions 418 a and 418 bfollowed by the two consecutive muted PRS positioning occasions 418 cand 418 d will repeat for the next muting sequence periodicity T_(REP)430.

To further improve hearability of PRS, positioning subframes may below-interference subframes that are transmitted without user datachannels. As a result, in ideally synchronized networks, PRS may receiveinterference from other cell's PRS with the same PRS pattern index(i.e., with the same frequency shift), but not from data transmissions.The frequency shift, in LTE, for example, is defined as a function of aPRS ID for a cell or other transmission point (TP) (denoted as N_(ID)^(PRS)) or as a function of a Physical Cell Identifier (PCI) (denoted asN_(ID) ^(cell)) if no PRS ID is assigned, which results in an effectivefrequency re-use factor of 6.

To also improve hearability of a PRS (e.g., when PRS bandwidth islimited such as with only 6 resource blocks corresponding to 1.4 MHzbandwidth), the frequency band for consecutive PRS positioning occasions(or consecutive PRS subframes) may be changed in a known and predictablemanner via frequency hopping. In addition, a cell supported by awireless node may support more than one PRS configuration (e.g., PRSconfiguration 400/500), where each PRS configuration may comprise adistinct frequency offset (vshift), a distinct carrier frequency, adistinct bandwidth, a distinct code sequence, and/or a distinct sequenceof PRS positioning occasions with a particular number of subframes(N_(PRS)) per positioning occasion and a particular periodicity(T_(PRS)). In some implementation, one or more of the PRS configurationssupported in a cell may be for a directional PRS and may then haveadditional distinct characteristics such as a distinct direction oftransmission, a distinct range of horizontal angles and/or a distinctrange of vertical angles. Further enhancements of a PRS may also besupported by a wireless node.

FIG. 5 illustrates an exemplary wireless communications system 500according to various aspects of the disclosure. In the example of FIG.5, a UE 115 is attempting to calculate an estimate of its position, orassist another entity (e.g., a base station or core network component,another UE, a location server, a third party application, etc.) tocalculate an estimate of its position. The UE 115 may communicatewirelessly with a plurality of base stations 105-1, 105-2, and 105-3(collectively, base stations 105), which may correspond to anycombination of base stations 105 in FIG. 1, using RF signals andstandardized protocols for the modulation of the RF signals and theexchange of information packets. By extracting different types ofinformation from the exchanged RF signals, and utilizing the layout ofthe wireless communications system 500 (i.e., the base stationslocations, geometry, etc.), the UE 115 may determine its position, orassist in the determination of its position, in a predefined referencecoordinate system. In an aspect, the UE 115 may specify its positionusing a two-dimensional coordinate system; however, the aspectsdisclosed herein are not so limited, and may also be applicable todetermining positions using a three-dimensional coordinate system, ifthe extra dimension is desired. Additionally, while FIG. 5 illustratesone UE 115 and three base stations 105, as will be appreciated, theremay be more UEs 115 and more or fewer base stations 105.

To support position estimates, the base stations 105 may be configuredto broadcast reference RF signals (e.g., PRS, CRS, CSI-RS,synchronization signals, etc.) to UEs 115 in their coverage area toenable a UE 115 to measure characteristics of such reference RF signals.For example, the UE 115 may use the OTDOA positioning method, and the UE115 may measure the RSTD between specific reference RF signals (e.g.,PRS, CRS, CSI-RS, etc.) transmitted by different pairs of network nodes(e.g., base stations 105, antennas of base stations 105, etc.).

Generally, RSTDs are measured between a reference network node (e.g.,base station 105-1 in the example of FIG. 5) and one or more neighbornetwork nodes (e.g., base stations 105-2 and 105-3 in the example ofFIG. 5). The reference network node remains the same for all RSTDsmeasured by the UE 115 for any single positioning use of OTDOA and wouldtypically correspond to the serving cell for the UE 115 or anothernearby cell with good signal strength at the UE 115. In an aspect, wherea measured network node is a cell supported by a base station, theneighbor network nodes would normally be cells supported by basestations different from the base station for the reference cell and mayhave good or poor signal strength at the UE 115. The locationcomputation can be based on the measured time differences (e.g., RSTDs)and knowledge of the network nodes' locations and relative transmissiontiming (e.g., regarding whether network nodes are accuratelysynchronized or whether each network node transmits with some known timedifference relative to other network nodes).

To assist positioning operations, a location server (e.g., locationserver 170) may provide OTDOA assistance data to the UE 115 for thereference network node (e.g., base station 105-1 in the example of FIG.5) and the neighbor network nodes (e.g., base stations 105-2 and 105-3in the example of FIG. 5) relative to the reference network node. Forexample, the assistance data may provide the center channel frequency ofeach network node, various reference RF signal configuration parameters(e.g., the number of consecutive positioning subframes, periodicity ofpositioning subframes, muting sequence, frequency hopping sequence,reference RF signal ID, reference RF signal bandwidth), a network nodeglobal ID, and/or other cell related parameters applicable to OTDOA, asdescribed above. The OTDOA assistance data may also indicate the servingcell for the UE 115 as the reference network node.

In an aspect, while the location server (e.g., positioning engine 101)may send the assistance data to the UE 115, alternatively, theassistance data can originate directly from the network nodes (e.g.,base stations 105) themselves (e.g., in periodically broadcastedoverhead messages, etc.). Alternatively, the UE 115 can detect neighbornetwork nodes itself without the use of assistance data.

In the example of FIG. 5, the measured time differences between thereference cell of base station 105-1 and the neighboring cells of basestations 105-2 and 105-3 are represented as τ₂-τ₁ and τ₃-τ₁, where τ₁,τ₂, and τ₃ represent the transmission time of a reference RF signal fromthe transmitting antenna(s) of base station 105-1, 105-2, and 105-3,respectively, to the UE 115, and includes any measurement noise at theUE 115. The UE 115 may then convert the ToA measurements for differentnetwork nodes to RSTD measurements (e.g., as defined in 3GPP TS 36.214entitled “Physical layer; Measurements”) and (optionally) send them tothe positioning engine 101. Using (i) the RSTD measurements, (ii) theknown absolute or relative transmission timing of each network node,(iii) the known position(s) of physical transmitting antennas for thereference and neighboring network nodes, and/or (iv) directionalreference RF signal characteristics such as a direction of transmission,the UE's 115 position may be determined (either by the UE 115 or thepositioning engine 101).

The ToA T_(i) at the UE 115 for the shortest path from base station i is

${T_{i} = {\tau_{i} + \frac{D_{i}}{c}}},$where D_(i) is the Euclidean distance between the base stations i withlocation (q_(i)) and the UE 115 with location (p), c is the speed oflight in the air (299700 km/s), and q_(i) is known through the cellinformation database. The Euclidean distance (i.e., the line distancebetween two points) is given by:

${{c\left( {T_{i} - \tau_{i}} \right)} = {\sqrt{2}R\sqrt{1 - {{\sin\left( \varphi_{1} \right)}{\sin\left( \varphi_{2} \right)}} - {{\cos\left( \varphi_{1} \right)}{\cos\left( \varphi_{2} \right)}{\cos\left( {\beta_{1} - \beta_{2}} \right)}}}}},$

where D is the distance between two points on the surface of the earth,R is the radius of the earth (6371 km), φ₁, φ₂ is the latitude (inradians) of the first point and the latitude (in radians) of the secondpoint, respectively, and β₁, β₂ is the longitude (in radians) of thefirst point and the latitude (in radians) of the second point,respectively.

In order to identify the ToA of a reference RF signal transmitted by agiven network node, the UE 115 first jointly processes all the resourceelements (REs) on the channel on which that network node (e.g., basestation 105) is transmitting the reference RF signal, and performs aninverse Fourier transform to convert the received RF signals to the timedomain. The conversion of the received RF signals to the time domain isreferred to as estimation of the Channel Energy Response (CER). The CERshows the peaks on the channel over time, and the earliest “significant”peak should therefore correspond to the ToA of the reference RF signal.Generally, a UE will use a noise-related quality threshold to filter outspurious local peaks, thereby presumably correctly identifyingsignificant peaks on the channel. For example, a UE 115 may chose a ToAestimate that is the earliest local maximum of the CER that is at leastX dB higher than the median of the CER and a maximum Y dB lower than themain peak on the channel. The UE 115 determines the CER for eachreference RF signal from each network node in order to determine the ToAof each reference RF signal from the different network nodes.

When the UE 115 obtains a location estimate itself using OTDOA measuredtime differences, the necessary additional data (e.g., network nodes'locations and relative transmission timing) may be provided to the UE115 by a location server (e.g., positioning engine 101). In someimplementations, a location estimate for the UE 115 may be obtained(e.g., by the UE 115 itself or by the positioning engine 101) from OTDOAmeasured time differences and from other measurements made by the UE 115(e.g., measurements of signal timing from GPS or other GNSS satellites).In these implementations, known as hybrid positioning, the OTDOAmeasurements may contribute towards obtaining the UE's 115 locationestimate but may not wholly determine the location estimate.

Uplink Time Difference of Arrival (UTDOA) is a similar positioningmethod to OTDOA, but is based on uplink reference RF signals transmittedby the UE (e.g., UE 115). Further, transmission and/or receptionbeamforming at the network node and/or UE 115 can enable widebandbandwidth at the cell edge for increased precision. Beam refinements mayalso leverage channel reciprocity procedures in 5G NR.

FIG. 6 illustrates a simplified environment and an exemplary techniquefor determining a position of a UE 115. The UE 115 may communicatewirelessly with a plurality of base stations (gNBs) 105-1, 105-2, 105-3(sometimes collectively referred to as base stations 105) using radiofrequency (RF) signals and standardized protocols for the modulation ofthe RF signals and the exchanging of information packets. By extractingdifferent types of information from the exchanged signals, and utilizingthe layout of the network (i.e., the network geometry), the UE 115 maydetermine its position in a predefined reference coordinate system. Asshown in FIG. 6, the UE 115 may specify its position (x, y) using atwo-dimensional coordinate system; however, the aspects disclosed hereinare not so limited, and may also be applicable to determining positionsusing a three-dimensional coordinate system, if the extra dimension isdesired. Additionally, while three base stations are shown in FIG. 6,aspects may utilize additional gNBs.

In order to determine its position (x, y), the UE 115 may first need todetermine the network geometry. The network geometry can include thepositions of each of the base stations 105 in a reference coordinatesystem ((xk, yk), where k=1, 2, 3). The network geometry may be providedto the UE 115 in any manner, such as, for example, providing thisinformation in beacon signals, providing the information using adedicated server external on an external network, providing theinformation using uniform resource identifiers, etc.

The UE 115 may then determine a distance (dk, where k=1, 2, 3) to eachof the base stations 105-k. As will be described in more detail below,there are a number of different approaches for estimating thesedistances (dk) by exploiting different characteristics of the RF signalsexchanged between the UE 115 and base stations 105-1, 105-2, 105-3. Suchcharacteristics may include, as will be discussed below, the round triptime (RTT) of the signals, and/or the strength of the signals (RSSI).

In other aspects, the distances (dk) may in part be determined orrefined using other sources of information that are not associated withthe base stations 105. For example, other positioning systems, such asGPS, may be used to provide a rough estimate of dk. (Note that it islikely that GPS may have insufficient signal strength in the anticipatedoperating environments (indoors, metropolitan, etc.) to provide aconsistently accurate estimate of dk. However, GPS signals may becombined with other information to assist in the position determinationprocess.) Other relative positioning devices may reside in the UE 115which can be used as a basis to provide rough estimates of relativeposition and/or direction (e.g., on-board accelerometers).

Once each distance is determined, the UE 115 can then solve for itsposition (x, y) by using a variety of known geometric techniques, suchas, for example, trilateration. From FIG. 6, it can be seen that theposition of the UE 115 ideally lies at the common intersection of all ofthe circles 602, 604, and 606 drawn using dotted lines. Each circlebeing defined by radius dk and center (xk, yk), where k=1, 2, 3. Inpractice, the intersection of these circles may not lie at a singlepoint due to the noise and other errors in the networking system.

Determining the distance between the UE 115 and each base station 105may involve exploiting time information of the RF signals. In an aspect,determining the RTT of signals exchanged between the UE 115 and any basestation can be performed and converted to a distance (dk). RTTtechniques can measure the time between sending a signaling message andreceiving a response. These methods may utilize calibration to removeany processing delays.

As used herein, a “network node” may be a base station (e.g., a basestation 105), a cell of a base station (e.g., a cell of a base station105), a remote radio head, an antenna of a base station (e.g., anantenna of a base station 105, where the locations of the antennas of abase station are distinct from the location of the base station itself),an array of antennas of a base station (e.g., an array of antennas of abase station 105, where the locations of the antenna arrays are distinctfrom the location of the base station itself), or any other networkentity capable of transmitting reference RF signals. Further, as usedherein, a “network node” may refer to either a network node or a UE.

The term “base station” may refer to a single physical transmissionpoint or to multiple physical transmission points that may or may not beco-located. For example, where the term “base station” refers to asingle physical transmission point, the physical transmission point maybe an antenna of the base station (e.g., a base station 105)corresponding to a cell of the base station. Where the term “basestation” refers to multiple co-located physical transmission points, thephysical transmission points may be an array of antennas (e.g., as in aMultiple Input-Multiple Output (MIMO) system or where the base stationemploys beamforming) of the base station. Where the term “base station”refers to multiple non-co-located physical transmission points, thephysical transmission points may be a Distributed Antenna System (DAS)(a network of spatially separated antennas connected to a common sourcevia a transport medium) or a Remote Radio Head (RRH) (a remote basestation connected to a serving base station). Alternatively, thenon-co-located physical transmission points may be the serving basestation receiving the measurement report from the UE (e.g., UE 115) anda neighbor base station whose reference RF signals the UE 115 ismeasuring.

The term “cell” refers to a logical communication entity used forcommunication with a base station (e.g., over a carrier), and may beassociated with an identifier for distinguishing neighboring cells(e.g., a Physical Cell Identifier (PCID), a Virtual Cell Identifier(VCID)) operating via the same or a different carrier. In some examples,a carrier may support multiple cells, and different cells may beconfigured according to different protocol types (e.g., Machine-TypeCommunication (MTC), Narrowband Internet-of-Things (NB-IoT), EnhancedMobile Broadband (eMBB), or others) that may provide access fordifferent types of devices. In some cases, the term “cell” may refer toa portion of a geographic coverage area (e.g., a sector) over which thelogical entity operates.

An “RF signal” comprises an electromagnetic wave that transportsinformation through the space between a transmitter and a receiver. Asused herein, a transmitter may transmit a single “RF signal” or multiple“RF signals” to a receiver. However, the receiver may receive multiple“RF signals” corresponding to each transmitted RF signal due to thepropagation characteristics of RF signals through multipath channels.The same transmitted RF signal on different paths between thetransmitter and receiver may be referred to as a “multipath” RF signal.

The term “position estimate” is used herein to refer to an estimate of aposition for a UE 115, which may be geographic (e.g., may comprise alatitude, longitude, and possibly altitude) or civic (e.g., may comprisea street address, building designation, or precise point or area withinor nearby to a building or street address, such as a particular entranceto a building, a particular room or suite in a building, or a landmarksuch as a town square). A position estimate may also be referred to as a“location,” a “position,” a “fix,” a “position fix,” a “location fix,” a“location estimate,” a “fix estimate,” or by some other term. The meansof obtaining a location estimate may be referred to generically as“positioning,” “locating,” or “position fixing.” A particular solutionfor obtaining a position estimate may be referred to as a “positionsolution.” A particular method for obtaining a position estimate as partof a position solution may be referred to as a “position method” or as a“positioning method.”

FIGS. 7A and 7B illustrate a performance comparison between comb-1 vs.comb-4. As used herein the term “comb-N” will represent that 1 of everyN subcarriers of a given bandwidth of a given symbol contain a PRS,without frequency staggering (i.e., all OFDM symbols carrying a PRScontain the PRS on the same subcarriers). It will be appreciated thatfor comb-1, each subcarrier of the transmission bandwidth contains aPRS, whereas with comb-4, 1 in every 4 subcarriers of the transmissionbandwidth contain a PRS. In FIG. 7A, each shaded block representsresource elements/subcarriers containing a PRS. The illustration ofcomb-1 (full comb) indicates that each subcarrier has a PRS that can beobtained by the UE. It will be appreciated that not all PRS have to bein the same OFDM symbol, but can be dispersed across various OFDMsymbols. Regardless, the UE will have a PRS to be sampled in eachsubcarrier/tone. LTE, by way of example, uses a comb-1 or near comb-1transmission after de-staggering. For example, LTE may transmit PRSalong with additional symbols, such as CRS, which after de-staggeringresults in a PRS, e.g., 5 of every 6 subcarriers containing PRS for anear comb value of 1.2. Other ratios of subcarriers are used in LTE, butresult in a destaggered comb value of less than 2.

In contrast, the comb-4 pattern (without additional frequencystaggering) is illustrated with several resource elements/subcarriersthat do not have a PRS to sample (e.g., empty blocks) and the PRS inevery fourth subcarrier/tone. FIG. 7B is a graph illustrating theperformance differences between the comb-1 and comb-4 PRS structures. Itcan be seen that performance loss appears in the tail of the cumulativedistribution function (CDF) (after 60% percentile). Comb-4 has energyper resource element (EPRE) ratio of 6 dB. Although, the performance isbetter with the comb-1 configuration, it also increases the overhead andreduces the effective bandwidth of a given subframe, so there is anadvantage to use less than all subcarriers in a subframe for PRStransmission.

FIG. 8 is a graph 800 illustrating a comb-4 channel energy response(CER) and potential alias issue. If a cell is far away, there can bealiasing due to the frequency domain subsampling, e.g., with comb-N,where N is 2 or more. Where the comb value is less than 2 (e.g., nearcomb-1), such as used in LTE, significant aliasing may not be producedand may not require resolution. For example, in the comb-4 PRSstructure, subsampling in the frequency domain results in the multiplepeaks (four), as illustrated. A distance from each peak (x-axis inmeters (m)) can be assumed based on the speed of light and timedifference. As illustrated, there is approximately 1000 m between peaks.Also, as illustrated, the detected strongest peak 810, is an alias ofthe true peak 820. This can create an offset of 2500 m, as illustratedin the example of FIG. 8. Establishing a RSTD search window based on anestimated location of the UE could mitigate the aliasing problem, when aPRS structure with a comb spacing that is equal to or greater thancomb-2. For example, a RSTD search window 850 may be −2 μs to +2 μsaround the 100 m position. Using the RSTD search window 850, the truepeak 820 will be detected and the alias peak 810 would be discarded andthe correct location will be identified. It will also be appreciatedthat the allowable RSTD search window is based on the PRS structure. Ifwe have a PRS structure which does not fully sample the frequencydomain, then the allowable/maximum-size of the uncertainty window shouldbe different to address the different PRS structure. For example, if theallowable RSTD search window 850 was too large, it would not preventdetection of an alias peak (e.g. 810), so the allowable RSTD searchwindow should be less than the peak to peak distance caused by thesubsampling.

FIG. 9 illustrates a simplified environment 900 including UE 115 andbase station 105 and illustrates distances d1, d2, d3, and d4illustrated by circles 902, 904, 906, and 908, corresponding to eachpeak in the comb-4 CER graph 800, illustrated in FIG. 8. As illustrated,UE 115 resides at distance d3 on dotted circle 906, which, thus,provides the true position measurement value. The remaining distances,d1, d2 and d4 on dash-dot circles 902, 904, and 908, respectively, arefalse position measurement values and need to be eliminated in order toaccurate determine the position of the UE 115.

In general, a PRS signal occupying a subset of tones of the PRSbandwidth may produce an aliasing ambiguity resulting in multiplepossible positioning measurement results. For example, even withfrequency staggering, aliasing ambiguities may occur, e.g., if the combsafter de-staggering do not result in a comb-1 PRS. For example, a PRSsignal may be comb-4 with frequency staggering, but may have less than 4OFDM symbols, so in each group of 4 tones, PRS occupies 1, 2, or 3 tonesand the remaining tones are not occupied by PRS. Such a configurationmay also lead to aliasing ambiguities. In particular, if PRS occupiestones 1 and 3, e.g., where tones are numbered 1, 2, 3, 4 within eachblock of 4, then after de-staggering, it is effectively a comb-2 signal,as described above.

Accordingly, techniques are described herein for resolving aliasingambiguities when using a PRS signal occupying a subset of tones of thePRS bandwidth, which in some implementations may be a comb-N, with N≥2,PRS signal that produces N possible positioning measurement results dueto aliasing ambiguities.

When a PRS signal occupying a subset of tones of the PRS bandwidth isused, e.g., such as with a CSI-RS transmission or a tracking referencesignal (TRS), the true positioning measurement result may be determinedby resolving the aliasing ambiguity with a previous position estimate.For example, the UE 115 may use the PRS signal to generate multiplepossible positioning measurement results, e.g., TOA, RSTD, or Rx−Tx. TheUE 115 may obtain a rough distance to the base station 105 and may usethe rough distance to identify the true positioning measurement from themultiple possible positioning measurement results. For example, the UE115 may determine a rough distance to the base station 105 based on aprevious position estimate for the UE 115 and a known location of thebase station 105, which may be provided in assistance data from thepositioning engine 101. The previous position estimate may be determinedby the UE 115, e.g., using RAT dependent process, such as OTDOA, RTT,etc., or from a RAT independent process, such as GNSS, vision basedpositioning, dead reckoning, etc. The previous position estimate may beprovided to the UE 115 by a network entity, such as the positioningengine 101.

The UE 115 may determine a rough distance to the base station 105 usinga two-stage or multi-stage PRS configuration. For example, the PRSsignals may be configured with a first signal that is a comb-1 PRSsignal but with possibly low bandwidth, that will produce a coarseposition measurement result, but without aliasing ambiguities, i.e., asingle position measurement result is produced. For example, the comb-1PRS, both DL and UL, may be a PRS as defined in Rel16 NR in 3GPPTechnical Specification (TS) 38.211. The UL PRS may sometimes bereferred to as SRS for positioning, or more precisely may be referred toas SRS configured by the information element (IE) SRS-Positioning-Confg.The comb-1 PRS signal may be an effective comb-1 signal afterde-staggering. The PRS signals may be configured with a second signalthat is the PRS signal occupying a subset of tones of a PRS bandwidth,which may have a higher bandwidth and thus produces a more accurateposition but includes aliasing ambiguities. For example, the PRS may bea RS as defined in Rel15 in 3GPP TS 38.211. The coarse positionmeasurement result produced by the comb-1 PRS signal may be used toresolve the aliasing ambiguities of the PRS signal. The comb-1 PRSsignal may have a lower bandwidth and longer period than the PRS signalin order to reduce overhead. By way of example, in some cases, the firstPRS configuration may be based on a synchronization signal block (SSB)signal or a subset of an SSBs. In some implementations, there may bemore than two stages in the PRS configuration. For example, a pluralityof PRS configurations may be used jointly to resolve the aliasingambiguity. The PRS configurations, for example, may be separate PRSconfigurations, with an indication provided indicating that they shouldbe jointly processed.

The use of a two-stage (or multi-stage) PRS configuration may implicitlyindicate to the UE 115 the ambiguity resolution parameters. For example,the positioning engine 101 may indicate that the UE 115 is expected toresolve the ambiguity from a PRS signal in the second stage based on theinclusion of a first stage with a comb-1 PRS signal that can be used todetermine a coarse position measurement result.

Moreover, parameters in one PRS configuration may be implicit orindicated indirectly based on parameters explicitly configured in theother PRS configuration. For example, the bandwidths or periodicities ofthe two (or multiple) PRS configuration may have a known relationship,e.g., a comb-N PRS signal may be twice that of the comb-1 PRS signal, orboth the comb-N and comb-1 PRS signals may have the same periodicity.

Alternatively, both PRS signals may be merged into a single PRSconfiguration. For example, an M OFDM symbol PRS may be used, where thefirst M1 OFDM symbols are effective comb-1 after de-staggering, and theremaining M-M1 OFDM symbols are effective comb-N after de-staggering.

In some examples, once the UE 115 has resolved the aliasing ambiguity,the UE 115 may provide an indication to the network entity, e.g.,positioning engine 101, about how the ambiguity was resolved, and thepositioning engine 101 may accordingly narrow search-windows to be usedby the UE 115 for the base station 105. For example, the search windowsmay be configured so that only one correlation peak is found within thesearch window.

In some examples, the aliasing ambiguities may be resolved by thepositioning engine 101. For example, in a UE-assisted positioningprocess, the UE 115 may use the PRS signal to generate multiple possiblepositioning measurement results, e.g., TOA, RSTD, or Rx−Tx. The UE 115may report the possible positioning measurement results to thepositioning engine 101. In one example, the UE 115 may report only oneof the multiple possible positioning measurements results, e.g., theearliest (or latest) TOA measurement, to the positioning engine 101 andthe positioning engine 101 may determine the remaining positioningmeasurement results based on the known aliasing ambiguities, thepositioning measurement result provided, and the known relationship ofthe provided positioning measurement result (e.g., first or last) withrespect to the remaining possible positioning measurement results. Thepositioning engine 101 may be explicitly informed about the aliasingambiguity, e.g., from the base station 105, or may infer it from the PRSconfiguration used, e.g., lack of staggering.

As with the UE 115, the positioning engine 101 may resolve the aliasingambiguity to determine the true positioning measurement result based ona previous position estimate for the UE 115. For example, thepositioning engine 101 may determine a rough distance between the UE 115and the base station 105 and may use the rough distance to identify thetrue positioning measurement from the multiple possible positioningmeasurement results. The positioning engine 101 may determine a roughdistance between the UE 115 and the base station 105 based on a previousposition estimate for the UE 115 and a known location of the basestation 105.

The positioning engine 101 may also determine a rough distance betweenthe UE 115 and the base station 105 using the two-stage or multi-stagePRS configuration, discussed above. For example, UE 115 may measure thetwo-stage or multi-stage PRS signals discussed above, and may transmitthe signals to the positioning engine 101. The positioning engine 101may use the comb-1 PRS signals to generate a positioning measurementresult that can resolve the aliasing ambiguity produced by the PRSsignals, as discussed above.

Once the positioning engine 101 resolves the aliasing ambiguity, thepositioning engine 101 may provide inform the UE 115 about how toresolve the ambiguity, and the UE 115 may use the information to resolvealiasing ambiguities in positioning measurement results. For example,the positioning engine 101 may implicitly inform the UE 115 about how toresolve the ambiguity by configuring a narrow search window to be usedby the UE 115 for the base station 105. The search window may beconfigured so that, even if there are multiple correlation peaksresulting from the PRS signal, only one correlation peak may be foundwithin the search window. In some example, it may be mandatory for thepositioning engine 101 to inform the UE 115 about how to resolve theambiguity, while in other examples, it may be optional and if not soinformed, the UE 115 may report possible positioning measurement resultsto the positioning engine 101 and the positioning engine 101 may resolvethe ambiguity.

Additionally, while the above techniques are describe referring to DLPRS received by the UE 115 from the base station 105, similar techniquesmay be applied for uplink (UL) SRS signals transmitted by the UE 115 andreceived by one or more base stations 105. For example, a base station105 may receive from the UE a PRS signal occupying a subset of tones ofa PRS bandwidth, e.g., which may be an SRS signal, and may sendpositioning measurement results to the positioning engine 101 to resolvethe ambiguity as discussed above. In some examples, the base station maydetermine multiple possible positioning measurement results and mayforward only one of the possible positioning measurement results, e.g.,the earliest (or latest) TOA measurement, to the positioning engine 101.The positioning engine 101 may determine the remaining positioningmeasurement results based on the known aliasing ambiguities, thepositioning measurement result provided, and the known relationship ofthe provided positioning measurement result (e.g., first or last) withrespect to the remaining possible positioning measurement results. Thepositioning engine 101 may resolve the aliasing ambiguity using aprevious position estimate or using a two-stage (or multi-stage) PRSconfiguration, as discussed above.

FIG. 10 shows a procedure which may be used to support position methodsin which DL PRS signals occupying a subset of tones of the PRS bandwidthare transmitted by the base station 105 are used.

At stage 1, a location server, e.g., positioning engine 101, sends aRequest Capabilities message to UE 115 via the base station 105 andintervening network entities, such as an AMF (not shown) to request thepositioning capabilities of UE 115. The Request Capabilities message mayindicate the type of capabilities needed. For example, in the presentillustration, OTDOA is desired and, thus, the UE's OTDOA capabilitiesare requested.

At stage 2, the UE 115 returns a Provide Capabilities message topositioning engine 101 comprising the positioning capabilities of UE115. UE 115 may include its capability to support OTODA (or otherdesired positioning methods) and may include the ability to support PRSsignals occupying a subset of tones of the PRS bandwidth.

At stage 3, the positioning engine 101 sends an OTDOA InformationRequest to the base station 105. For example, the OTDOA InformationRequest may request that the base station 105 provide informationrelated to OTDOA, which may include the PRS configuration or aliasingambiguity information.

At stage 4, the base station 105 may return an OTDOA InformationResponse to the positioning engine 101 providing the requestedinformation, including the PRS configuration or aliasing ambiguityinformation. The OTDOA Information Request of stage 3 and the OTDOAInformation Response of stage 4 may be, e.g., Long Term Evolution (LTE)Positioning Protocol A (LPPa) or New Radio Position Protocol A (NRPPa)messages.

At stage 5, the positioning engine 101 may generate OTDOA assistancedata (AD), e.g., using the OTDOA Information Response from the basestation 105 or OTDOA information obtained elsewhere for base station105. The OTDOA assistance data may include assistance data for the basestation 105 and other base stations that may be nearby. The OTDOAassistance data, for example, may include the locations of basestations, which may be used by the UE 115 in the resolution of anyaliasing ambiguities, as discussed above. If the positioning engine 101has previously determined an estimated position of the UE 115, the OTDOAassistance data may include a previously position of the UE 115, whichmay be used by the UE 115 in the resolution of any aliasing ambiguities,as discussed above. If the positioning engine 101 has previouslyresolved an aliasing ambiguity for the UE 115, the OTDOA assistance datamay include a search window that is narrowly configured to contain onlyone of the correlation peaks from a PRS signal from the base station105, which corresponds to a single position measurement result out basedon the plurality of possible position measurement results.

At stage 6, the positioning engine 101 provides the OTDOA AD to the UE115.

At stage 7, the positioning engine 101 sends a Request LocationInformation message to the UE 115 to request RSTD measurements. Themessage may include, e.g., the type of location measurements, thedesired accuracy, response time, etc.

At stage 8 a, the base station 105 transmits PRS signals that arereceived by the UE 115. The PRS signals may occupy a subset of tones ofa PRS bandwidth, and may be comb-N PRS signals, where N is 2 or more.The subset of tones of the PRS bandwidth produces a plurality ofpossible positioning results. In some implementations, the PRS signalmay be CSI-RS signals. In some examples, the PRS signals may includemultiple stages, such as a comb-1 or effective comb-1 signal afterde-staggering, and the PRS signal. The comb-1 PRS signal for example,may be an SSB signal or a subset of an SSB signal.

At stage 8 b, the UE 115 may transmits UL PRS signals, e.g., SRS forpositioning or SRS configured by the IE SRS-Positioning-Config., thatare received by the base station 105. The UL PRS signals may occupy asubset of tones of a PRS bandwidth, and may be comb-N PRS signals, whereN is 2 or more. The subset of tones of the PRS bandwidth produces aplurality of possible positioning results. In some examples, the UL PRSsignals may include multiple stages, such as a comb-1 or effectivecomb-1 signal after de-staggering, and the PRS signal.

At stage 9 a, the UE 115 performs the requested positioning measurementusing the PRS transmissions received from the base station 105 at stage8 a. For example, the positioning measurements may be one or more ofTOA, RSTD, or Rx−Tx. The UE may use the OTDOA AD from stage 6 to performthe requested positioning measurements. In one implementation, the UE115 may determine may resolve an aliasing ambiguity in the positioningmeasurement results to determine the true positioning measurement resultfrom plurality of possible positioning measurement results. In oneimplementation, the UE 115 may use a previous estimated position of theUE 115, obtained using RAT dependent or independent methods or obtainedfrom the positioning engine 101, e.g., in OTDOA AD from stage 6, todetermine the true positioning measurement result. For example, the UE115 may resolve the aliasing ambiguity to determine the true positioningmeasurement result obtaining a rough distance between the UE and thebase station, which may be obtained from a previous estimated positionof the UE 115, and using the rough distance to identify the truepositioning measurement result. In another example, the UE 115 mayresolve the aliasing ambiguity to determine the true positioningmeasurement result using a comb-1 PRS signal received from stage 8 a. Inanother example, the UE 115 may resolve the aliasing ambiguity todetermine the true positioning measurement result using a plurality ofPRS signals, each occupying s subset of tones of the PRS bandwidth, anddetermining a single position measurement result from the plurality ofPRS signals, which is used to identify the true positioning measurementresult. In another example, the UE 115 may use a narrow search windowfor the base station 105 received with the OTDOA AD from stage 6 toresolve the aliasing ambiguity to determine the true positioningmeasurement result.

At stage 9 b, the base station 105 may perform positioning measurementsusing the PRS transmissions received from the UE 115 at stage 8 b. Forexample, the positioning measurements may be one or more of TOA orRx−Tx. In one implementation, the base station 105 resolves an aliasingambiguity in the positioning measurement results to determine the truepositioning measurement result from a plurality of possible positioningmeasurement results. For example, the base station 105 may resolve thealiasing ambiguity to determine the true positioning measurement resultusing a comb-1 PRS signal received from stage 8 b.

At stage 10, if a UE-based position determination process is used, theUE 115 may determine the UE location using the true positioningmeasurement result after the aliasing ambiguity has been resolved, alongwith locations of base station 105 and other base stations 105, notshown, which may have been received in the assistance data provided atstage 6.

At stage 11 a, the UE 115 provides the location information based onmeasurements obtained from the base station 105 and other base stations105, not shown, to the positioning engine 101. The location information,for example, may be the true positioning measurement results, afterresolving the aliasing ambiguities. In another example, the locationinformation may be one or more measurements prior to resolving anyaliasing ambiguities, e.g., where the positioning engine 101 willresolve the aliasing ambiguities, e.g., the location information mayinclude only a single positioning measurement result, e.g., the first orlast positioning measurement result of the plurality of possiblepositioning measurement results. In one example, the locationinformation may be the two-stage or multi-stage PRS signals received bythe UE 115 at stage 8 a. If UE-based positioning determination isperformed, the location information may be the UE location determined atstage 10 and may further include information such as the positioningmeasurements or the positioning measurement results after the aliasingambiguity has been resolved.

At stage 11 b, the base station 105 provides the location informationbased on PRS received from UE 115 at stage 8 b and measurementsobtained, if any, at stage 9 b.

At stage 12, the positioning engine 101 may resolve the aliasingambiguities if the UE 115 did not resolve the aliasing ambiguities instage 9 a or the base station 105 did not resolve the aliasing ambiguityat stage 9 b. The positioning engine 101, for example, may resolve theambiguity in a manner similar to the UE 115 as discussed in stage 9 a.The positioning engine 101 may determine the UE location using thereceived location information, e.g., in a UE-assisted positioningprocess, or the positioning engine 101 may confirm the UE location ifprovide at stage 11 a in a UE-based positioning process. The positioningengine 101 may provide the UE location to an external client.

The above described technique may be applied to uplink PRS signals,sometimes referred to as SRS for positioning or SRS configured by the IESRS-Positioning-Cofig., that occupy a subset of tones of a PRSbandwidth, transmitted by the UE 115 as well, with the UE beingconfigured to transmit on different SRS resources or resource sets,which have different effective comb densities after de-staggering, forexample, a low bandwidth effective-comb-1 together with a high bandwidtheffective comb-N(N≥2) SRS transmission.

FIG. 11 shows a process flow 1100 illustrating a method for positionlocation performed by a user equipment (UE), such as the UE 115.

Process flow 1100 may start at block 1102, where the UE receives from abase station a positioning reference signal (PRS) occupying a subset oftones of a PRS bandwidth, wherein the subset of tones of the PRSbandwidth produces a plurality of possible positioning results, which isillustrated, e.g., at stage 8 a in FIG. 10. The PRS signal, for example,may be a Channel state information reference signal (CSI-RS) or atracking reference signal (TRS). At block 1104, a true positioningmeasurement result based on the plurality of possible positioningmeasurement results is determined from the received PRS signal, e.g., asillustrated at stage 9 a or stages 11 a and 12 of FIG. 10.

In one implementation, the positioning measurement results that areproduced from the PRS signal comprise one or more of Time of Arrival(TOA), Reference Signal Time Difference (RSTD), or reception totransmission difference (Rx−Tx).

In one implementation, the PRS signal is a comb-N signal, where N≥2, andwherein the comb-N PRS signal produces N possible positioningmeasurement results due to aliasing ambiguities, e.g., as discussed atstage 8 a of FIG. 10.

In one implementation, determining the true positioning measurementresult from the received PRS signal may include receiving a comb-1 PRSsignal from the base station, determining a single positioningmeasurement result from the comb-1 PRS signal; and using the singlepositioning measurement result to identify the true positioningmeasurement result based on the plurality of possible positioningmeasurement results, e.g., as discussed at stages 8 a and 9 a of FIG.10. For example, the comb-1 PRS signal from the base station may be anSSB signal.

In one implementation, determining the true positioning measurementresult from the received PRS signal may include receiving a plurality ofPRS signals each occupying a subset of tones of the PRS bandwidth fromthe base station; determining a positioning measurement result from theplurality of PRS signals; and using the positioning measurement resultto identify the true positioning measurement result based on theplurality of possible positioning measurement results, e.g., asdiscussed at stage 9 a of FIG. 10.

In one implementation, determining the true positioning measurementresult from the received PRS signal may include determining theplurality of possible positioning measurement results from the PRSsignal; obtaining a rough distance between the UE and the base station;and using the rough distance to identify the true positioningmeasurement result based on the plurality of possible positioningmeasurement results, e.g., as discussed at stage 9 a of FIG. 10. Therough distance between the UE and the base station may be obtained, inone example, by obtaining a previous position estimate for the UE and aknown location of the base station; and determining the rough distancebetween the UE and the base station based on the previous positionestimate and the known location of the base station, e.g., as discussedat stage 9 a of FIG. 10. The previous position estimate may be obtainedusing a Radio Access Technology (RAT) independent process. The previousposition estimate may be obtained from a network entity, such as thepositioning engine 101. In one example, the UE may transmit informationrelated to the true positioning measurement result to a network entity;and may receive from the network entity a search window associated withthe base station, wherein the search window is configured by the networkentity based on the information related to the true positioningmeasurement result to find only a single positioning measurement resultfrom PRS signals received from the base station, e.g., as discussed atstage 9 a of FIG. 10.

In one implementation, determining the true positioning measurementresult from the received PRS signal may include receiving a searchwindow associated with the base station from a network entity, whereinthe search window is configured to find only a single positioningmeasurement result in the plurality of possible positioning measurementresults; and using the search window to find the true positioningmeasurement result based on the plurality of possible positioningmeasurement results, e.g., as discussed at stage 9 a of FIG. 10.

In one implementation, the UE may perform UE-based positiondetermination or UE-assisted position determination to determine alocation of the UE using the true positioning measurement result, e.g.,as discussed at stages 10, 11 a and 12 of FIG. 10. For example, forUE-based position determination, the UE may determine the location ofthe UE using the true positioning measurement result, e.g. along withadditional information such as the locations of base stations. ForUE-assisted position determination, the UE may transmit the truepositioning measurement result to a location engine and the locationengine may determine the location of the UE using the true positioningmeasurement.

FIG. 12 shows a process flow 1200 illustrating a method for positionlocation for a user equipment (UE) performed by a base station, such asbase station 105.

Process flow 1200 may start at block 1202, where the base stationreceives from the UE a positioning reference signal (PRS) each occupyinga subset of tones of a PRS bandwidth, wherein the subset of tones of thePRS bandwidth produces a plurality of possible positioning results,e.g., as discussed at stage 8 b of FIG. 10. The PRS signal, for example,may be a sounding reference signal (SRS). At block 1204, the basestation sends location information to a positioning engine in thewireless network based on multiple PRS signal for the positioning engineto determine a true positioning measurement result based on theplurality of possible positioning measurement results from the receivedPRS signal, e.g., as discussed at stage 11 b of FIG. 10.

In one implementation, the positioning measurement results that areproduced from the PRS signal comprise one or more of Time of Arrival(TOA) or reception to transmission difference (Rx−Tx).

In one implementation, the PRS signal is a comb-N signal, where N≥2, andwherein the comb-N PRS signal produces N possible positioningmeasurement results due to aliasing ambiguities.

In one implementation, the base station may determine the plurality ofpossible positioning measurement results from the PRS signal, whereinthe location information comprises one positioning measurement resultbased on the plurality of possible positioning measurement results,e.g., as discussed at stage 9 b of FIG. 10.

In one implementation, the base station may further receive one or morecomb-1 PRS signals from the UE, wherein the location informationcomprises one or more comb-1 PRS signals and the PRS signal, e.g., asdiscussed at stage 8 b of FIG. 10. The positioning engine may determinethe true positioning measurement result based on the plurality ofpossible positioning measurement results based on a single positioningmeasurement result determined by the one or more comb-1 PRS signals andthe plurality of possible positioning measurement results determinedfrom the PRS signal.

FIG. 13 shows a process flow 1300 illustrating a method for positionlocation for a user equipment (UE) performed by a positioning engine,such as positioning engine 101 shown in FIG. 1, which may be a locationserver such as Location Management Function (LMF) in a NR network or aSecure User Plane Location (SUPL) Location Platform (SLP) in LTE.

Process flow 1300 may start at block 1302, where the positioning enginereceives a location information from a first entity in the wirelessnetwork determined from a positioning reference signal (PRS) signaloccupying a subset of tones of a PRS bandwidth, received by the firstentity from a second entity in the wireless network, wherein the firstentity is one of the UE, such as UE 115, and a base station, such asbase station 105, and the second entity is the other of the UE and thebase station, wherein the subset of tones of the PRS bandwidth producesa plurality of possible positioning results, e.g., as illustrated atstages 11 a and 11 b in FIG. 10. By way of example, the first entity maybe the UE and the second entity may be the base station and the PRSsignal may be a Channel state information reference signal (CSI-RS) or atracking reference signal (TRS). In another example, the first entitymay be the base station and the second entity may be the UE, and the PRSsignal may be a sounding reference signal (SRS). At block 1304, a truepositioning measurement result based on the plurality of possiblepositioning measurement results is determined from the received locationinformation, e.g., as discussed at stage 12 of FIG. 10.

In one implementation, the positioning measurement results that areproduced from the PRS signal comprise one or more of Time of Arrival(TOA), Reference Signal Time Difference (RSTD), or reception totransmission difference (Rx−Tx).

In one implementation, the PRS signal is a comb-N signal, where N≥2, andwherein the comb-N PRS signal produces N possible positioningmeasurement results due to aliasing ambiguities.

In one implementation, the true positioning measurement result may bedetermined by obtaining a previous position estimate for the UE and aknown location of the base station; determining the rough distancebetween the UE and the base station based on the previous positionestimate and the known location of the base station; and using the roughdistance to identify the true positioning measurement result based onthe plurality of possible positioning measurement results, e.g., asdiscussed at stages 9 a and 12 of FIG. 10. For example, the receivedlocation information may be one positioning measurement result receivedfrom the first entity, and the positioning engine may obtain informationabout the aliasing ambiguities; and determine the plurality of possiblepositioning measurement results from the one positioning measurementresult received from the first entity and the information about thealiasing ambiguities. The information about the aliasing ambiguities maybe received from the second entity or may be inferred from aconfiguration of the PRS signals.

In one implementation, the positioning engine may configure for thefirst entity a search window associated with the second entity that isbased on the true positioning measurement result so that the firstentity can find only a single positioning measurement result from PRSsignals received from the second entity; and may transmit the searchwindow to the first entity, e.g., as discussed at stages 5 and 6 of FIG.10.

In one implementation, the received location information may be one ormore comb-1 PRS signals and the PRS signal, wherein the positioningengine may determine the true positioning measurement result bydetermining a single positioning measurement result from the one or morecomb-1 PRS signals; determining the plurality of possible positioningmeasurement results from the PRS signal; and using the singlepositioning measurement result to identify the true positioningmeasurement result based on the plurality of possible positioningmeasurement results, e.g., as discussed at stages 9 a and 12 of FIG. 10.

In one implementation, a location of the UE is determined using the truepositioning measurement result, e.g., as discussed at stage 12 of FIG.10.

FIG. 14 is a diagram illustrating an example of a hardwareimplementation of UE 1400, such as UE 115. The UE 1400 may include awireless transceiver 1402 to wirelessly communicate with a base station,e.g., base station 105. The UE 1400 may also include additionaltransceivers, such a wireless local area network (WLAN) transceiver1406, as well as an SPS receiver 1408 for receiving and measuringsignals from SPS SVs. The UE 1400 may further include one or moresensors 1410, such as cameras, accelerometers, gyroscopes, electroniccompass, magnetometer, barometer, etc. The UE 1400 may further include auser interface 1412 that may include e.g., a display, a keypad or otherinput device, such as virtual keypad on the display, through which auser may interface with the UE 1400. The UE 1400 further includes one ormore processors 1404 and memory 1420, which may be coupled together withbus 1416. The one or more processors 1404 and other components of the UE1400 may similarly be coupled together with bus 1416, a separate bus, ormay be directly connected together or coupled using a combination of theforegoing. The memory 1420 may contain executable code or softwareinstructions that when executed by the one or more processors 1404 causethe one or more processors to operate as a special purpose computerprogrammed to perform the algorithms disclosed herein.

As illustrated in FIG. 14, the memory 1420 may include one or morecomponents or modules that may be implemented by the one or moreprocessors 1404 to perform the methodologies described herein. While thecomponents or modules are illustrated as software in memory 1420 that isexecutable by the one or more processors 1404, it should be understoodthat the components or modules may be dedicated hardware either in theone or more processors 1404 or off the processors.

As illustrated, the memory 1420 may include assistance data receive unit1422 that configures the one or more processors 1404 to receiveassistance data, via wireless transceiver 1402 from a location server,e.g., positioning engine 101. The assistance data may include, e.g.,locations of base stations, a previous estimated position for the UE1400 or a search window.

A PRS receive unit 1424 configures the one or more processors 1404 toreceive, via wireless transceiver 1402, a positioning reference signal(PRS) signal occupying a subset of tones of a PRS bandwidth from a basestation, such as base station 105. The PRS signal may be a comb-Nsignal, where N≥2. The PRS signal produces a plurality of possiblepositioning measurement results due to aliasing ambiguities, whereinpositioning measurement results produced by the PRS may comprise one ormore of Time of Arrival (TOA), Reference Signal Time Difference (RSTD),or reception to transmission difference (Rx−Tx). The PRS receive unit1424 may configure the one or more processors 1404 to receive comb-N PRSsignals, where N may be 1 or more, e.g., where a two-stage ormulti-stage PRS configuration is used.

The memory 1420 may further include a position measurement determinationunit 1426 that configures the one or more processors 1404 to determineone or more, e.g., N, possible positioning measurement result from thereceived PRS signal. For example, the positioning measurement resultsmay be one or more of TOA, RSTD, Rx−Tx.

The memory 1420 may further include a coarse distance unit 1428 thatconfigures the one or more processors 1404 to obtain a rough distancebetween the UE and the base station. The coarse distance unit 1428 mayconfigure the one or more processors 1404 to use a previous positionestimate obtained using position estimate unit 1432, along with a knownlocation of the base station, obtained from AD received using the ADreceive unit 1422 to determine the rough distance.

The memory 1420 may further include a true position measurementdetermination unit 1430 that configures the one or more processors 1404to determine the true positioning measurement result from the receivedPRS signal. For example, the rough distance obtained using coarsedistance unit 1428 may be used to identify the true positioningmeasurement result based on the plurality of possible positioningmeasurement results. In another example, the true positioningmeasurement result may be identified using a comb-1 signal or aplurality of comb-N signals received using the PRS receive unit 1424 anda single position measurement determined therefrom using the positionmeasurement determination unit 1426.

The memory 1420 may include a position estimate unit 1432 thatconfigures the one or more processors 1404 to obtain a position estimatefor the UE 1400. For example, the one or more processors 1404 may beconfigured to determine a position estimate from wireless signalsreceived via wireless transceiver 1402, using OTDOA, RTT, etc. The oneor more processors 1404 may be configured to determine a positionestimate from RAT independent methods, such as from signals receivedfrom WLAN transceiver 1406, SPS receiver 1408, or sensors 1410, e.g.,using GNSS, vision based positioning or dead reckoning. The positionestimate unit 1432 may configure the one or more processors 1404 toobtain a position estimate from a network entity, such as positioningengine 101, via the wireless transceiver 1402.

A location information transmit unit 1434 configures the one or moreprocessors to transmit location information to a positioning engine 101,via the wireless transceiver 1402. The location information, forexample, may be a positioning measurement result or a position estimatedetermined for the UE 1400.

The methodologies described herein may be implemented by various meansdepending upon the application. For example, these methodologies may beimplemented in hardware, firmware, software, or any combination thereof.For a hardware implementation, the one or more processors 1404 may beimplemented within one or more application specific integrated circuits(ASICs), digital signal processors (DSPs), digital signal processingdevices (DSPDs), programmable logic devices (PLDs), field programmablegate arrays (FPGAs), processors, controllers, micro-controllers,microprocessors, electronic devices, other electronic units designed toperform the functions described herein, or a combination thereof.

For an implementation of UE 1400 involving firmware and/or software, themethodologies may be implemented with modules (e.g., procedures,functions, and so on) that perform the separate functions describedherein. Any machine-readable medium tangibly embodying instructions maybe used in implementing the methodologies described herein. For example,software codes may be stored in a memory (e.g. memory 1420) and executedby one or more processors 1404, causing the one or more processors 1404to operate as a special purpose computer programmed to perform thetechniques disclosed herein. Memory may be implemented within the one orprocessors 1404 or external to the one or more processors 1404. As usedherein the term “memory” refers to any type of long term, short term,volatile, nonvolatile, or other memory and is not to be limited to anyparticular type of memory or number of memories, or type of media uponwhich memory is stored.

If implemented in firmware and/or software, the functions performed byUE 1400 may be stored as one or more instructions or code on anon-transitory computer-readable storage medium such as memory 1420.Examples of storage media include computer-readable media encoded with adata structure and computer-readable media encoded with a computerprogram. Computer-readable media includes physical computer storagemedia. A storage medium may be any available medium that can be accessedby a computer. By way of example, and not limitation, suchcomputer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage, semiconductor storage, orother storage devices, or any other medium that can be used to storedesired program code in the form of instructions or data structures andthat can be accessed by a computer; disk and disc, as used herein,includes compact disc (CD), laser disc, optical disc, digital versatiledisc (DVD), floppy disk and Blu-ray disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Combinations of the above should also be included within the scope ofcomputer-readable media.

In addition to storage on computer-readable storage medium, instructionsand/or data for UE 1400 may be provided as signals on transmission mediaincluded in a communication apparatus. For example, a communicationapparatus comprising part or all of UE 1400 may include a transceiverhaving signals indicative of instructions and data. The instructions anddata are stored on non-transitory computer readable media, e.g., memory1420, and are configured to cause the one or more processors 1404 tooperate as a special purpose computer programmed to perform thetechniques disclosed herein. That is, the communication apparatusincludes transmission media with signals indicative of information toperform disclosed functions. At a first time, the transmission mediaincluded in the communication apparatus may include a first portion ofthe information to perform the disclosed functions, while at a secondtime the transmission media included in the communication apparatus mayinclude a second portion of the information to perform the disclosedfunctions.

Thus, a UE, such as the UE 1400, may be configured for position locationand may include a means for receiving from a base station a positioningreference signal (PRS) signal occupying a subset of tones of a PRSbandwidth, wherein the subset of tones of the PRS bandwidth produces aplurality of possible positioning results, which may be, e.g., thewireless transceiver 1402 and one or more processors 1404 with dedicatedhardware for implementing executable code or software instructions inmemory 1420 such as the PRS receive unit 1424. A means for determining atrue positioning measurement result based on the plurality of possiblepositioning measurement results from the received PRS signal may be,e.g., the one or more processors 1404 with dedicated hardware forimplementing executable code or software instructions in memory 1420such as the true position measurement determination unit 1430.

In one implementation, the means for determining the true positioningmeasurement result from the received PRS signal may include a means forreceiving a comb-1 PRS signal from the base station, which may be, e.g.,the wireless transceiver 1402 and one or more processors 1404 withdedicated hardware for implementing executable code or softwareinstructions in memory 1420 such as the PRS receive unit 1424; a meansfor determining a positioning measurement result from the comb-1 PRSsignal, which may be, e.g., the one or more processors 1404 withdedicated hardware for implementing executable code or softwareinstructions in memory 1420 such as the position measurementdetermination unit 1426; and a means for using the positioningmeasurement result to identify the true positioning measurement resultbased on the plurality of possible positioning measurement results,which may be, e.g., the one or more processors 1404 with dedicatedhardware for implementing executable code or software instructions inmemory 1420 such as the true position measurement determination unit1430.

In one implementation, the means for determining the true positioningmeasurement result from the received PRS signal may include a means forreceiving a plurality of PRS signals each occupying a subset of tones ofthe PRS bandwidth from the base station, which may be, e.g., thewireless transceiver 1402 and one or more processors 1404 with dedicatedhardware for implementing executable code or software instructions inmemory 1420 such as the PRS receive unit 1424; a means for determining asingle positioning measurement result from the plurality of PRS signalswhich may be, e.g., the wireless transceiver 1402 and one or moreprocessors 1404 with dedicated hardware for implementing executable codeor software instructions in memory 1420 such as the PRS receive unit1424, which may be, e.g., the one or more processors 1404 with dedicatedhardware for implementing executable code or software instructions inmemory 1420 such as the position measurement determination unit 1426;and a means for using the single positioning measurement result toidentify the true positioning measurement result based on the pluralityof possible positioning measurement results, which may be, e.g., the oneor more processors 1404 with dedicated hardware for implementingexecutable code or software instructions in memory 1420 such as the trueposition measurement determination unit 1430.

In one implementation, the means for determining the true positioningmeasurement result from the received PRS signal includes a means fordetermining the plurality of possible positioning measurement resultsfrom the PRS signal, which may be, e.g., the one or more processors 1404with dedicated hardware for implementing executable code or softwareinstructions in memory 1420 such as the position measurementdetermination unit 1426; a means for obtaining a rough distance betweenthe UE and the base station, which may be, e.g., the one or moreprocessors 1404 with dedicated hardware for implementing executable codeor software instructions in memory 1420 such as the coarse distance unit1428; and a means for using the rough distance to identify the truepositioning measurement result based on the plurality of possiblepositioning measurement results, which may be, e.g., the one or moreprocessors 1404 with dedicated hardware for implementing executable codeor software instructions in memory 1420 such as the true positionmeasurement determination unit 1430. The means for obtaining the roughdistance between the UE and the base station may include a means forobtaining a previous position estimate for the UE and a known locationof the base station, which may be, e.g., the one or more processors 1404with dedicated hardware for implementing executable code or softwareinstructions in memory 1420 such as the position estimate unit 1432; anda means for determining the rough distance between the UE and the basestation based on the previous position estimate and the known locationof the base station, which may be, e.g., the wireless transceiver 1402and one or more processors 1404 with dedicated hardware for implementingexecutable code or software instructions in memory 1420 such as the ADreceive unit 1422 and the coarse distance unit 1428.

In one implementation, the UE may further include a means fortransmitting information related to the true positioning measurementresult to a network entity, which may be, e.g., the wireless transceiver1402 and one or more processors 1404 with dedicated hardware forimplementing executable code or software instructions in memory 1420such as the location information transmit unit 1434. A means forreceiving from the network entity a search window associated with thebase station, wherein the search window is configured by the networkentity based on the information related to the true positioningmeasurement result to find only a single positioning measurement resultfrom PRS signals occupying a subset of tones of the PRS bandwidthreceived from the base station may be, e.g., the wireless transceiver1402 and one or more processors 1404 with dedicated hardware forimplementing executable code or software instructions in memory 1420such as the AD receive unit 1434.

In one implementation, the means for determining the true positioningmeasurement result from the received PRS signal includes a means forreceiving a search window associated with the base station from anetwork entity, wherein the search window is configured to find only asingle positioning measurement result in the plurality of possiblepositioning measurement results, which may be, e.g., the wirelesstransceiver 1402 and one or more processors 1404 with dedicated hardwarefor implementing executable code or software instructions in memory 1420such as the AD receive unit 1434. A means for using the search window tofind the true positioning measurement result based on the plurality ofpossible positioning measurement results may be, e.g., the one or moreprocessors 1404 with dedicated hardware for implementing executable codeor software instructions in memory 1420 such as the true positioningmeasurement determination unit 1430.

FIG. 15 is a diagram illustrating an example of a hardwareimplementation of a base station 1500, such as base station 105. Thebase station 1500 includes, e.g., hardware components such as anexternal interface 1502, which may be a wired and/or wireless interfacecapable of connecting to an positioning engine, such as positioningengine 101, and capable of wirelessly connecting to UE 115. The basestation 1500 includes a one or more processors 1504 and memory 1510,which may be coupled together with bus 1506. The memory 1510 may containexecutable code or software instructions that when executed by the oneor more processors 1504 cause the one or more processors 1504 to operateas a special purpose computer programmed to perform the procedures andtechniques disclosed herein.

As illustrated in FIG. 15, the memory 1510 includes one or morecomponents or modules that when implemented by the one or moreprocessors 1504 implements the methodologies as described herein. Whilethe components or modules are illustrated as software in memory 1510that is executable by the one or more processors 1504, it should beunderstood that the components or modules may be dedicated hardwareeither in the processor or off processor.

As illustrated, the memory 1510 may include a PRS receive unit 1512configures the one or more processors 1504 to receive, via externalinterface 1502, a positioning reference signal (PRS) signal occupying asubset of tones of a PRS bandwidth from the UE, such as UE 115, whereinthe subset of tones of the PRS bandwidth produces a plurality ofpossible positioning results. The PRS signal may be a comb-N signal andmay produces N possible positioning measurement results due to aliasingambiguities. Positioning measurement results produced by the PRS maycomprise one or more of Time of Arrival (TOA) or reception totransmission difference (Rx−Tx). The PRS receive unit 1512 may configurethe one or more processors 1504 to receive comb-N PRS signals, where Nmay be 1 or more, e.g., where a two-stage or multi-stage PRSconfiguration is used. The PRS signal from the UE, for example, may be asounding reference signal (SRS).

The memory 1510 may further include a position measurement determinationunit 1514 that configures the one or more processors 1504 to determineone or more, e.g., N, possible positioning measurement result from thereceived PRS signal. For example, the positioning measurement resultsmay be one or more of TOA, RSTD, Rx−Tx.

The memory 1510 may further include a location information transmit unit1516 that configures the one or more processors 1504 to transmitlocation information to a positioning engine 101, via the externalinterface 1502. The location information, for example, may be apositioning measurement result determined using position measurementdetermination unit 1514 or the PRS signals received using the PRSreceive unit 1512.

The methodologies described herein may be implemented by various meansdepending upon the application. For example, these methodologies may beimplemented in hardware, firmware, software, or any combination thereof.For a hardware implementation, the one or more processors may beimplemented within one or more application specific integrated circuits(ASICs), digital signal processors (DSPs), digital signal processingdevices (DSPDs), programmable logic devices (PLDs), field programmablegate arrays (FPGAs), processors, controllers, micro-controllers,microprocessors, electronic devices, other electronic units designed toperform the functions described herein, or a combination thereof.

For an implementation involving firmware and/or software, themethodologies may be implemented with modules (e.g., procedures,functions, and so on) that perform the separate functions describedherein. Any machine-readable medium tangibly embodying instructions maybe used in implementing the methodologies described herein. For example,software codes may be stored in a memory and executed by one or moreprocessor units, causing the processor units to operate as a specialpurpose computer programmed to perform the algorithms disclosed herein.Memory may be implemented within the processor unit or external to theprocessor unit. As used herein the term “memory” refers to any type oflong term, short term, volatile, nonvolatile, or other memory and is notto be limited to any particular type of memory or number of memories, ortype of media upon which memory is stored.

If implemented in firmware and/or software, the functions may be storedas one or more instructions or code on a non-transitorycomputer-readable storage medium. Examples include computer-readablemedia encoded with a data structure and computer-readable media encodedwith a computer program. Computer-readable media includes physicalcomputer storage media. A storage medium may be any available mediumthat can be accessed by a computer. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage,semiconductor storage, or other storage devices, or any other mediumthat can be used to store desired program code in the form ofinstructions or data structures and that can be accessed by a computer;disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and Blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media.

In addition to storage on computer-readable storage medium, instructionsand/or data may be provided as signals on transmission media included ina communication apparatus. For example, a communication apparatus mayinclude a transceiver having signals indicative of instructions anddata. The instructions and data are stored on non-transitory computerreadable media, e.g., memory 1510, and are configured to cause the oneor more processors to operate as a special purpose computer programmedto perform the procedures and techniques disclosed herein. That is, thecommunication apparatus includes transmission media with signalsindicative of information to perform disclosed functions. At a firsttime, the transmission media included in the communication apparatus mayinclude a first portion of the information to perform the disclosedfunctions, while at a second time the transmission media included in thecommunication apparatus may include a second portion of the informationto perform the disclosed functions.

Thus, a base station, such as the base station 1500, may be configuredposition location for a user equipment (UE) and may include a means forreceiving from the UE a positioning reference signal (PRS) signaloccupying a subset of tones of a PRS bandwidth, wherein the subset oftones of the PRS bandwidth produces a plurality of possible positioningresults, which may be, e.g., the external interface 1502 and one or moreprocessors 1504 with dedicated hardware for implementing executable codeor software instructions in memory 1510 such as the PRS receive unit1512. A means for sending a location information to a positioning enginein the wireless network based on the PRS signal for the positioningengine to determine a true positioning measurement result based on theplurality of possible positioning measurement results from the receivedPRS signal may be, e.g., the external interface 1502 and one or moreprocessors 1504 with dedicated hardware for implementing executable codeor software instructions in memory 1510 such as the location informationtransmit unit 1516.

In one implementation, the base station may further include a means fordetermining the plurality of possible positioning measurement resultsfrom the PRS signal, wherein the location information comprises onepositioning measurement result based on the plurality of possiblepositioning measurement results, which may be, e.g., the one or moreprocessors 1504 with dedicated hardware for implementing executable codeor software instructions in memory 1510 such as the position measurementdetermination unit 1514.

In one implementation, the base station may further include a means forreceiving one or more comb-1 PRS signals from the UE, wherein thelocation information comprises one or more comb-1 PRS signals and thePRS signal, which may be, e.g., the external interface 1502 and one ormore processors 1504 with dedicated hardware for implementing executablecode or software instructions in memory 1510 such as the PRS receiveunit 1512, wherein the positioning engine determines the truepositioning measurement result based on the plurality of possiblepositioning measurement results based on a single positioningmeasurement result determined by the one or more comb-1 PRS signals andthe plurality of possible positioning measurement results determinedfrom the PRS signal.

FIG. 16 is a diagram illustrating an example of a hardwareimplementation of a positioning engine, such as positioning engine 101,which may be a location server such as Location Management Function(LMF) in a NR network or a Secure User Plane Location (SUPL) LocationPlatform (SLP) in LTE. The positioning engine 1600 includes, e.g.,hardware components such as an external interface 1602, which may be awired or wireless interface capable of connecting to a base station 105and UE 115, e.g., via intermediate network entities. The positioningengine 1600 includes a one or more processors 1604 and memory 1610,which may be coupled together with bus 1606. The memory 1610 may containexecutable code or software instructions that when executed by the oneor more processors 1604 cause the one or more processors 1604 to operateas a special purpose computer programmed to perform the procedures andtechniques disclosed herein.

As illustrated in FIG. 16, the memory 1610 includes one or morecomponents or modules that when implemented by the one or moreprocessors 1604 implements the methodologies described herein. While thecomponents or modules are illustrated as software in memory 1610 that isexecutable by the one or more processors 1604, it should be understoodthat the components or modules may be dedicated hardware either in theprocessors 1604 or off processor.

As illustrated, the memory 1610 may include an assistance data unit 1612that configures the one or more processors 1604 to generate assistancedata and to forward the assistance data to a UE. The assistance data mayinclude, e.g., locations of base stations, a previous estimated positionfor the UE or a search window.

A location information receive unit 1614 configures the one or moreprocessors to receive location information from the UE 115 or basestation 105, via the external interface 1602. The location information,for example, may be a positioning measurement result or one or more PRSsignals occupying a subset of tones of a PRS bandwidth, wherein thesubset of tones of the PRS bandwidth produces a plurality of possiblepositioning results. The PRS signals may be, e.g., a channel stateinformation reference signal (CSI-RS) received by a UE or a soundingreference signal (SRS) received by a base station. The PRS signal may becomb-N signals that produce N possible positioning measurement resultsdue to aliasing ambiguities. Positioning measurement results produced bythe PRS signals may comprise one or more of Time of Arrival (TOA),Reference Signal Time Difference (RSTD), or reception to transmissiondifference (Rx−Tx)

The memory 1610 may include a position measurement determination unit1616 that configures the one or more processors 1604 to determine one ormore, e.g., N, possible positioning measurement result from the receivedlocation information. For example, if the location information includesone or more PRS signals, the position measurement determination unit1616 may configure the one or more processors 1604 to determine thepositioning measurement results, such as one or more of TOA, RSTD,Rx−Tx. If the location information includes a single positioningmeasurement result, the position measurement determination unit 1616 mayconfigure the one or more processors 1604 to determine the remainingpositioning measurement results from the received positioningmeasurement result and information from the aliasing ambiguity unit1618. The aliasing ambiguity unit 1618 may configure the one or moreprocessors 1604 to determine the aliasing ambiguity from informationreceived from the base station or UE, via the external interface 1602 orinferred from the configuration of the PRS signals. The positionmeasurement determination unit 1616 may configure the one or moreprocessors 1604 to determine one or more, e.g., N, possible positioningmeasurement result using PRS signals received as location information.The position measurement determination unit 1616 may configure the oneor more processors 1604 to determine a single position measurementresult from a comb-1 PRS signal, or from jointly processing multiple PRSsignals received as location information.

The memory 1610 may include a position estimate unit 1620 thatconfigures the one or more processors 1604 to determine a positionestimate for the UE. For example, the one or more processors 1604 may beconfigured to determine a position estimate from the received locationinformation, using OTDOA, RTT, etc.

The memory 1610 may further include a coarse distance unit 1622 thatconfigures the one or more processors 1604 to determine a rough distancebetween the UE and the base station. The coarse distance unit 1622 mayconfigure the one or more processors 1604 to use a previous positionestimate, obtained using position estimate unit 1620, along with a knownlocation of the base station.

The memory 1610 may further include a true position measurementdetermination unit 1624 that configures the one or more processors 1604to determine the true positioning measurement result. For example, therough distance obtained using coarse distance unit 1622 may be used toidentify the true positioning measurement result from the N possiblepositioning measurement results. In another example, the truepositioning measurement result may be identified using a comb-1 signalor a plurality of comb-N signals received using the location informationreceive unit 1614 and a single position measurement determined therefromusing the position measurement determination unit 1616.

The memory 1610 may include a search window unit 1626 that configuresthe one or more processors 1604 to generate a search window based on thedetermined true positioning measurement result determined or receivedusing the location information receive unit 1614. The search window unit1626, for example, configures the one or more processors 1604 to producea search window that is narrow enough that only a single positioningmeasurement result is found from received PRS signals. The resultingsearch window may be forwarded to the UE or the base station usingassistance data unit 1612.

The methodologies described herein may be implemented by various meansdepending upon the application. For example, these methodologies may beimplemented in hardware, firmware, software, or any combination thereof.For a hardware implementation, the one or more processors may beimplemented within one or more application specific integrated circuits(ASICs), digital signal processors (DSPs), digital signal processingdevices (DSPDs), programmable logic devices (PLDs), field programmablegate arrays (FPGAs), processors, controllers, micro-controllers,microprocessors, electronic devices, other electronic units designed toperform the functions described herein, or a combination thereof.

For an implementation involving firmware and/or software, themethodologies may be implemented with modules (e.g., procedures,functions, and so on) that perform the separate functions describedherein. Any machine-readable medium tangibly embodying instructions maybe used in implementing the methodologies described herein. For example,software codes may be stored in a memory (e.g. memory 1610) and executedby one or more processor units (e.g. processors 1604), causing theprocessor units to operate as a special purpose computer programmed toperform the techniques and procedures disclosed herein. Memory may beimplemented within the processor unit or external to the processor unit.As used herein the term “memory” refers to any type of long term, shortterm, volatile, nonvolatile, or other memory and is not to be limited toany particular type of memory or number of memories, or type of mediaupon which memory is stored.

If implemented in firmware and/or software, the functions may be storedas one or more instructions or code on a non-transitorycomputer-readable storage medium. Examples include computer-readablemedia encoded with a data structure and computer-readable media encodedwith a computer program. Computer-readable media includes physicalcomputer storage media. A storage medium may be any available mediumthat can be accessed by a computer. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage,semiconductor storage, or other storage devices, or any other mediumthat can be used to store desired program code in the form ofinstructions or data structures and that can be accessed by a computer;disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and Blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media.

In addition to storage on computer-readable storage medium, instructionsand/or data may be provided as signals on transmission media included ina communication apparatus. For example, a communication apparatus mayinclude a transceiver having signals indicative of instructions anddata. The instructions and data are stored on non-transitory computerreadable media, e.g., memory 1610, and are configured to cause the oneor more processors (e.g. processors 1604) to operate as a specialpurpose computer programmed to perform the techniques and proceduresdisclosed herein. That is, the communication apparatus includestransmission media with signals indicative of information to performdisclosed functions. At a first time, the transmission media included inthe communication apparatus may include a first portion of theinformation to perform the disclosed functions, while at a second timethe transmission media included in the communication apparatus mayinclude a second portion of the information to perform the disclosedfunctions.

A positioning engine, such as the positioning engine 1600, may beconfigured position location for a user equipment (UE) and may include ameans for receiving location information from a first entity in thewireless network determined from a positioning reference signal (PRS)signal occupying a subset of tones of a PRS bandwidth, received by thefirst entity from a second entity in the wireless network, wherein thefirst entity is one of the UE and a base station and the second entityis the other of the UE and the base station, wherein the subset of tonesof the PRS bandwidth produces a plurality of possible positioningresults, which may be, e.g., the external interface 1602 and one or moreprocessors 1604 with dedicated hardware for implementing executable codeor software instructions in memory 1610 such as the location informationreceive unit 1614. A means for determining a true positioningmeasurement result based on the plurality of possible positioningmeasurement results from the received measurement result may be, e.g.,the one or more processors 1604 with dedicated hardware for implementingexecutable code or software instructions in memory 1610 such as the trueposition measurement determination unit 1624.

In one implementation, the means for determining the true positioningmeasurement result includes a means for obtaining a previous positionestimate for the UE and a known location of the base station, which maybe, e.g., the one or more processors 1604 with dedicated hardware forimplementing executable code or software instructions in memory 1610such as the position estimate unit 1620 and the assistance data unit1612; a means for determining a rough distance between the UE and thebase station based on the previous position estimate and the knownlocation of the base station, which may be, e.g., the one or moreprocessors 1604 with dedicated hardware for implementing executable codeor software instructions in memory 1610 such as the coarse position unit1622; and a means for using the rough distance to identify the truepositioning measurement result based on the plurality of possiblepositioning measurement results, which may be, e.g., the one or moreprocessors 1604 with dedicated hardware for implementing executable codeor software instructions in memory 1610 such as the true positionmeasurement determination unit 1624.

In one implementation, the received location information comprises onepositioning measurement result received from the first entity, and thepositioning engine may further include a means for obtaining informationabout the aliasing ambiguities, which may be, e.g., the one or moreprocessors 1604 with dedicated hardware for implementing executable codeor software instructions in memory 1610 such as the aliasing ambiguityunit 1618. A means for determining the plurality of possible positioningmeasurement results from the one positioning measurement result receivedfrom the first entity and the information about the aliasing ambiguitiesmay be, e.g., the one or more processors 1604 with dedicated hardwarefor implementing executable code or software instructions in memory 1610such as the position measurement determination unit 1616.

In one implementation, the positioning engine may further include ameans for configuring for the first entity a search window associatedwith the second entity that is based on the true positioning measurementresult so that the first entity can find only a single positioningmeasurement result from PRS signals received from the second entity,which may be, e.g., the one or more processors 1604 with dedicatedhardware for implementing executable code or software instructions inmemory 1610 such as the search window unit 1626. A means fortransmitting the search window to the first entity may be, e.g., theexternal interface 1602 and one or more processors 1604 with dedicatedhardware for implementing executable code or software instructions inmemory 1610 such as the assistance data unit 1612.

In one implementation, the received measurement result comprises one ormore comb-1 PRS signals and the PRS signal and the means for determiningthe true positioning measurement result may include a means fordetermining a single positioning measurement result from the one or morecomb-1 PRS signals, which may be, e.g., one or more processors 1604 withdedicated hardware for implementing executable code or softwareinstructions in memory 1610 such as the position measurementdetermination unit 1616. A means for determining the plurality ofpossible positioning measurement results from the PRS signal may be,e.g., one or more processors 1604 with dedicated hardware forimplementing executable code or software instructions in memory 1610such as the position measurement determination unit 1616. A means forusing the single positioning measurement result to identify the truepositioning measurement result based on the plurality of possiblepositioning measurement results may be, e.g., one or more processors1604 with dedicated hardware for implementing executable code orsoftware instructions in memory 1610 such as the true positionmeasurement determination unit 1624.

Reference throughout this specification to “one example”, “an example”,“certain examples”, or “exemplary implementation” means that aparticular feature, structure, or characteristic described in connectionwith the feature and/or example may be included in at least one featureand/or example of claimed subject matter. Thus, the appearances of thephrase “in one example”, “an example”, “in certain examples” or “incertain implementations” or other like phrases in various placesthroughout this specification are not necessarily all referring to thesame feature, example, and/or limitation. Furthermore, the particularfeatures, structures, or characteristics may be combined in one or moreexamples and/or features.

Some portions of the detailed description included herein are presentedin terms of algorithms or symbolic representations of operations onbinary digital signals stored within a memory of a specific apparatus orspecial purpose computing device or platform. In the context of thisparticular specification, the term specific apparatus or the likeincludes a general purpose computer once it is programmed to performparticular operations pursuant to instructions from program software.Algorithmic descriptions or symbolic representations are examples oftechniques used by those of ordinary skill in the signal processing orrelated arts to convey the substance of their work to others skilled inthe art. An algorithm is here, and generally, is considered to be aself-consistent sequence of operations or similar signal processingleading to a desired result. In this context, operations or processinginvolve physical manipulation of physical quantities. Typically,although not necessarily, such quantities may take the form ofelectrical or magnetic signals capable of being stored, transferred,combined, compared or otherwise manipulated. It has proven convenient attimes, principally for reasons of common usage, to refer to such signalsas bits, data, values, elements, symbols, characters, terms, numbers,numerals, or the like. It should be understood, however, that all ofthese or similar terms are to be associated with appropriate physicalquantities and are merely convenient labels. Unless specifically statedotherwise, as apparent from the discussion herein, it is appreciatedthat throughout this specification discussions utilizing terms such as“processing,” “computing,” “calculating,” “determining” or the likerefer to actions or processes of a specific apparatus, such as a specialpurpose computer, special purpose computing apparatus or a similarspecial purpose electronic computing device. In the context of thisspecification, therefore, a special purpose computer or a similarspecial purpose electronic computing device is capable of manipulatingor transforming signals, typically represented as physical electronic ormagnetic quantities within memories, registers, or other informationstorage devices, transmission devices, or display devices of the specialpurpose computer or similar special purpose electronic computing device.

In the preceding detailed description, numerous specific details havebeen set forth to provide a thorough understanding of claimed subjectmatter. However, it will be understood by those skilled in the art thatclaimed subject matter may be practiced without these specific details.In other instances, methods and apparatuses that would be known by oneof ordinary skill have not been described in detail so as not to obscureclaimed subject matter.

The terms, “and”, “or”, and “and/or” as used herein may include avariety of meanings that also are expected to depend at least in partupon the context in which such terms are used. Typically, “or” if usedto associate a list, such as A, B or C, is intended to mean A, B, and C,here used in the inclusive sense, as well as A, B or C, here used in theexclusive sense. In addition, the term “one or more” as used herein maybe used to describe any feature, structure, or characteristic in thesingular or may be used to describe a plurality or some othercombination of features, structures or characteristics. Though, itshould be noted that this is merely an illustrative example and claimedsubject matter is not limited to this example.

While there has been illustrated and described what are presentlyconsidered to be example features, it will be understood by thoseskilled in the art that various other modifications may be made, andequivalents may be substituted, without departing from claimed subjectmatter. Additionally, many modifications may be made to adapt aparticular situation to the teachings of claimed subject matter withoutdeparting from the central concept described herein.

Therefore, it is intended that claimed subject matter not be limited tothe particular examples disclosed, but that such claimed subject mattermay also include all aspects falling within the scope of appendedclaims, and equivalents thereof.

What is claimed is:
 1. A method for position location performed by auser equipment (UE), comprising: receiving from a base station apositioning reference signal (PRS) signal occupying a subset of tones ofa PRS bandwidth, wherein the subset of tones of the PRS bandwidthproduces a plurality of possible positioning measurement results causedby aliasing ambiguities; and determining a true positioning measurementresult based on the plurality of possible positioning measurementresults caused by the aliasing ambiguities from the received PRS signal,wherein determining the true positioning measurement result from thereceived PRS signal uses at least one of (i) a comb-1 PRS signalreceived from the base station, or (ii) a plurality of PRS signals eachoccupying a subset of tones of the PRS bandwidth received from the basestation, or (iii) a rough distance between the UE and the base station,or (iv) a search window associated with the base station that isconfigured to find only a single positioning measurement result in theplurality of possible positioning measurement results.
 2. The method ofclaim 1, wherein the positioning measurement results that are producedfrom the PRS signal comprise one or more of Time of Arrival (TOA),Reference Signal Time Difference (RSTD), or reception to transmissiondifference (Rx-Tx).
 3. The method of claim 1, wherein the PRS signal isa comb-N signal, where N≥2, and wherein the comb-N PRS signal produces Npossible positioning measurement results due to the aliasingambiguities.
 4. The method of claim 1, wherein the PRS signal comprisesa Channel state information reference signal (CSI-RS) or a trackingreference signal (TRS).
 5. The method of claim 1, wherein determiningthe true positioning measurement result from the received PRS signalcomprises: receiving the comb-1 PRS signal from the base station;determining a positioning measurement result from the comb-1 PRS signal;and using the positioning measurement result to identify the truepositioning measurement result from the plurality of possiblepositioning measurement results.
 6. The method of claim 5, wherein thecomb-1 PRS signal from the base station comprises a synchronizationsignal block (SSB) signal or a subset of an SSB signal.
 7. The method ofclaim 1, wherein determining the true positioning measurement resultfrom the received PRS signal comprises: receiving the plurality of PRSsignals each occupying a subset of tones of the PRS bandwidth from thebase station; determining a single positioning measurement result fromthe plurality of PRS signals; and using the single positioningmeasurement result to identify the true positioning measurement resultfrom the plurality of possible positioning measurement results.
 8. Themethod of claim 1, wherein determining the true positioning measurementresult from the received PRS signal comprises: determining the pluralityof possible positioning measurement results from the PRS signal;obtaining the rough distance between the UE and the base station; andusing the rough distance to identify the true positioning measurementresult based on the plurality of possible positioning measurementresults.
 9. The method of claim 8, wherein obtaining the rough distancebetween the UE and the base station comprises: obtaining a previousposition estimate for the UE and a known location of the base station;and determining the rough distance between the UE and the base stationbased on the previous position estimate and the known location of thebase station.
 10. The method of claim 9, wherein the previous positionestimate is obtained using a Radio Access Technology (RAT) independentprocess.
 11. The method of claim 9, wherein the previous positionestimate is obtained from a network entity.
 12. The method of claim 9,further comprising: transmitting information related to the truepositioning measurement result to a network entity; and receiving fromthe network entity a search window associated with the base station,wherein the search window is configured by the network entity based onthe information related to the true positioning measurement result tofind only a single positioning measurement result from PRS signalsoccupying a subset of tones of the PRS bandwidth received from the basestation.
 13. The method of claim 1, wherein determining the truepositioning measurement result from the received PRS signal comprises:receiving the search window associated with the base station from anetwork entity; and using the search window to find the true positioningmeasurement result based on the plurality of possible positioningmeasurement results.
 14. The method of claim 1, further comprisingperforming UE-based position determination or UE-assisted positiondetermination to determine a location of the UE using the truepositioning measurement result.
 15. A user equipment (UE) configured forperforming position location, comprising: a wireless transceiverconfigured to communicate with base stations in a wireless network; atleast one memory; and at least one processor coupled to the wirelesstransceiver and the at least one memory, the at least one processorconfigured to: receive from a base station, via the wirelesstransceiver, a positioning reference signal (PRS) signal occupying asubset of tones of a PRS bandwidth, wherein the subset of tones of thePRS bandwidth produces a plurality of possible positioning measurementresults caused by aliasing ambiguities; and determine a true positioningmeasurement result based on the plurality of possible positioningmeasurement results caused by the aliasing ambiguities from the receivedPRS signal, wherein determining the true positioning measurement resultfrom the received PRS signal uses at least one of (i) a comb-1 PRSsignal received from the base station, or (ii) a plurality of PRSsignals each occupying a subset of tones of the PRS bandwidth receivedfrom the base station, or (iii) a rough distance between the UE and thebase station, or (iv) a search window associated with the base stationthat is configured to find only a single positioning measurement resultin the plurality of possible positioning measurement results.
 16. The UEof claim 15, wherein the positioning measurement results that areproduced from the PRS signal comprise one or more of Time of Arrival(TOA), Reference Signal Time Difference (RSTD), or reception totransmission difference (Rx-Tx).
 17. The UE of claim 15, wherein the PRSsignal is a comb-N signal, where N≥2, and wherein the comb-N PRS signalproduces N possible positioning measurement results due to the aliasingambiguities.
 18. The UE of claim 15, wherein the PRS signal comprises aChannel state information reference signal (CSI-RS) or a trackingreference signal (TRS).
 19. The UE of claim 15, wherein the at least oneprocessor is configured to determine the true positioning measurementresult from the received PRS signal by being configured to: receive, viathe wireless transceiver, the comb-1 PRS signal from the base station;determine a positioning measurement result from the comb-1 PRS signal;and use the positioning measurement result to identify the truepositioning measurement result from the plurality of possiblepositioning measurement results.
 20. The UE of claim 19, wherein thecomb-1 PRS signal from the base station comprises a synchronizationsignal block (SSB) signal or a subset of an SSB signal.
 21. The UE ofclaim 15, wherein the at least one processor is configured to determinethe true positioning measurement result from the received PRS signal bybeing configured to: receive, via the wireless transceiver, theplurality of PRS signals each occupying a subset of tones of the PRSbandwidth from the base station; determine a single positioningmeasurement result from the plurality of PRS signals; and use the singlepositioning measurement result to identify the true positioningmeasurement result from the plurality of possible positioningmeasurement results.
 22. The UE of claim 15, wherein the at least oneprocessor is configured to determine the true positioning measurementresult from the received PRS signal by being configured to: determinethe plurality of possible positioning measurement results from the PRSsignal; obtain the rough distance between the UE and the base station;and use the rough distance to identify the true positioning measurementresult based on the plurality of possible positioning measurementresults.
 23. The UE of claim 22, wherein the at least one processor isconfigured to obtain the rough distance between the UE and the basestation by being configured to: obtain a previous position estimate forthe UE and a known location of the base station; and determine the roughdistance between the UE and the base station based on the previousposition estimate and the known location of the base station.
 24. The UEof claim 23, wherein the previous position estimate is obtained using aRadio Access Technology (RAT) independent process.
 25. The UE of claim23, wherein the previous position estimate is obtained from a networkentity.
 26. The UE of claim 23, wherein the at least one processor isfurther configured to: transmit, via the wireless transceiver,information related to the true positioning measurement result to anetwork entity; and receive from the network entity, via the wirelesstransceiver, a search window associated with the base station, whereinthe search window is configured by the network entity based on theinformation related to the true positioning measurement result to findonly a single positioning measurement result from PRS signals occupyinga subset of tones of the PRS bandwidth received from the base station.27. The UE of claim 15, wherein the at least one processor is configuredto determine the true positioning measurement result from the receivedPRS signal by being configured to: receive, via the wirelesstransceiver, the search window associated with the base station from anetwork entity; and use the search window to find the true positioningmeasurement result based on the plurality of possible positioningmeasurement results.
 28. The UE of claim 15, wherein the at least oneprocessor is configured to perform UE-based position determination orUE-assisted position determination to determine a location of the UEusing the true positioning measurement result.
 29. A method for positionlocation for a user equipment (UE) performed by a base station in awireless network, comprising: receiving from the UE a positioningreference signal (PRS) signal occupying a subset of tones of a PRSbandwidth, wherein the subset of tones of the PRS bandwidth produces aplurality of possible positioning measurement results caused by aliasingambiguities; and sending a location information to a positioning enginein the wireless network based on the PRS signal for the positioningengine to determine a true positioning measurement result based on theplurality of possible positioning measurement results caused by thealiasing ambiguities from the received PRS signal, wherein the truepositioning measurement result is determined based on at least one of(i) one or more comb-1 PRS signals received by the base station from theUE, or (ii) a rough distance between the UE and the base station. 30.The method of claim 29, wherein the positioning measurement results thatare produced from the PRS signal comprise one or more of Time of Arrival(TOA) or reception to transmission difference (Rx-Tx).
 31. The method ofclaim 29, wherein the PRS signal is a comb-N signal, where N≥2, andwherein the comb-N PRS signal produces N possible positioningmeasurement results due to the aliasing ambiguities.
 32. The method ofclaim 29, wherein the PRS signal comprises a sounding reference signal(SRS).
 33. The method of claim 29, further comprising: determining theplurality of possible positioning measurement results from the PRSsignal, wherein the location information comprises one positioningmeasurement result based on the plurality of possible positioningmeasurement results.
 34. The method of claim 29, further comprising:receiving the one or more comb-1 PRS signals from the UE, wherein thelocation information comprises one or more comb-1 PRS signals and thePRS signal; wherein the positioning engine determines the truepositioning measurement result based on the plurality of possiblepositioning measurement results based on a single positioningmeasurement result determined by the one or more comb-1 PRS signals andthe plurality of possible positioning measurement results determinedfrom the PRS signal.
 35. A base station in a wireless network configuredfor position location for a user equipment (UE), comprising: a wirelesstransceiver configured to communicate with UEs in the wireless network;at least one memory; and at least one processor coupled to the wirelesstransceiver and the at least one memory, the at least one processorconfigured to: receive from the UE, via the wireless transceiver, apositioning reference signal (PRS) signal occupying a subset of tones ofa PRS bandwidth, wherein the subset of tones of the PRS bandwidthproduces a plurality of possible positioning measurement results causedby aliasing ambiguities; and send, via the wireless transceiver, alocation information to a positioning engine in the wireless networkbased on the PRS signal for the positioning engine to determine a truepositioning measurement result based on the plurality of possiblepositioning measurement results caused by the aliasing ambiguities fromthe received PRS signal, wherein the true positioning measurement resultis determined based on at least one of (i) one or more comb-1 PRSsignals received by the base station from the UE, or (ii) a roughdistance between the UE and the base station.
 36. The base station ofclaim 35, wherein the positioning measurement results that are producedfrom the PRS signal comprise one or more of Time of Arrival (TOA) orreception to transmission difference (Rx-Tx).
 37. The base station ofclaim 35, wherein the PRS signal is a comb-N signal, where N≥2, andwherein the comb-N PRS signal produces N possible positioningmeasurement results due to the aliasing ambiguities.
 38. The basestation of claim 35, wherein the PRS signal comprises a soundingreference signal (SRS).
 39. The base station of claim 35, wherein the atleast one processor is further configured to: determine the plurality ofpossible positioning measurement results from the PRS signal, whereinthe location information comprises one positioning measurement resultbased on the plurality of possible positioning measurement results. 40.The base station of claim 35, wherein the at least one processor isfurther configured to: receive, via the wireless transceiver, the one ormore comb-1 PRS signals from the UE, wherein the location informationcomprises one or more comb-1 PRS signals and the PRS signal; wherein thepositioning engine determines the true positioning measurement resultbased on the plurality of possible positioning measurement results basedon a single positioning measurement result determined by the one or morecomb-1 PRS signals and the plurality of possible positioning measurementresults determined from the PRS signal.